Infectious Disorders

Share of 1-year-olds who have received the third dose of polio-containing vaccine. This may be either the oral or the inactivated polio vaccine. (Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Based on U.S. Public Health Service, U.S. Centers for Disease Control and Prevention, and World Health Organization. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

The reported figures include both wild- and vaccine-derived type polio infections that occurred indigenously and as imported cases. (Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Based on U.S. Public Health Service, U.S. Centers for Disease Control and Prevention, and World Health Organization. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Some cases of paralytic polio arise from vaccine-derived strains that have reverted to a form that can cause disease. There are three vaccine-derived strains of paralytic polio: VDPV1, 2, and 3. This shows cases of circulating vaccine-derived polioviruses. (Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Based on U.S. Public Health Service, U.S. Centers for Disease Control and Prevention, and World Health Organization. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Some cases of paralytic polio arise from vaccine-derived strains that have reverted to a form that can cause disease. The total number of cases across all three vaccine-derived strains is shown. (Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Based on U.S. Public Health Service, U.S. Centers for Disease Control and Prevention, and World Health Organization. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Estimates of the total number of paralytic polio cases due to wild polioviruses and vaccine-derived polioviruses. (Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Based on data from the World Health Organization and Duintjer Tebbens RJ, Pallansch MA, Cochi SL, et al. Economic analysis of the global polio eradication initiative. Vaccine 2010;29[2]:334-43. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Annual reported cases of polio that led to paralysis of the infected person. It includes both wild and vaccine-derived polioviruses. (Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Based on data from the World Health Organization and Global Polio Eradication Initiative. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Annual number of reported cases of paralytic polio per million people. This includes all reported cases from wild polioviruses and vaccine-derived polioviruses. (Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Based on data from the World Health Organization and population data based on various sources. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Countries are considered endemic if they have indigenous cases of polio from wild polioviruses.

Note: The following countries eradicated polio before 1960 but are hard to see on the map: Nauru (1910), Tuvalu (1936), Palau (1940), American Samoa, Niue and Tokelau (1950), Cayman Islands (1958), and Andorra and Cook Islands (1959).

(Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Based on data from the Global Polio Eradication Initiative. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Countries with wild poliovirus transmission are considered endemic. Countries are shown as polio-free (not certified) if they have demonstrated the absence of wild poliovirus transmission. When all countries in a World Health Organization region have recorded 0 cases for 3 consecutive years while meeting surveillance targets, the region can be certified as polio-free.

Note: The country Nauru already eradicated polio in 1910, which explains the starting date of this map. The first "larger" countries' eradication of polio can be seen after 1960.

(Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Based on data from the Global Polio Eradication Initiative. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

This includes reported cases of paralytic polio from any wild poliovirus strain (WPV1, WPV2, WPV3).

Note: The last case of WPV2 was reported in 1999, whereas the last case of WPV3 was reported in 2012. Cases shown since 2013 were all caused by WPV1.

(Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Based on data from the World Health Organization. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(A) 2000, (B) 2014, (C) 2016, and (D) 2023. Abbreviations: IPV, inactivated poliovirus vaccine; fIPV, fractional-dose inactivated poliovirus vaccine.

Note: Fractional-dose IPV can reduce the cost of polio immunization in campaigns. Two doses of fIPV can induce nearly 100% immunity if given in the appropriate schedule, whereas only using 40% of a full dose of IPV.

(Source: Sutter RW, Eisenhawer M, Molodecky NA, Verma H, Okayasu H. Inactivated poliovirus vaccine: recent developments and the tortuous path to global acceptance. Pathogens 2024;13[3]:224.) IPV introduction date: WHO Immunization, immunizationdata.who.int. Accessed on December 17, 2023. fIPV countries: Macklin GR, Mach O. Fractional-dose IPV in polio eradication. Lancet Infect Dis 2021;21[8]:1061-2. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

The funding given by each donor group to the Global Polio Eradication Initiative. This data is expressed in U.S. dollars, adjusted for inflation. Note: This data is expressed in constant 2021 US dollars.

(Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Based on data from the International Monetary Fund [via World Bank] and Global Polio Eradication Initiative. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. First published in November 2017, and last updated in May 2024. Available at: ourworldindata.org/polio. Accessed May 2024. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Controlling the disease can have lower costs in the short term, but the cumulative costs can quickly overtake those of eradication. (Source: Roser M, Ochmann S, Behrens H, Ritchie H, Dabonaite B. Eradication of diseases: which diseases could we eradicate in our lifetimes and how? First published in June 2014 and last revised in January 2024. Available at: ourworldindata.org/eradication-of-diseases. Accessed May 2024. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0 by Max Roser.)

Abbreviations: cVDPV, circulating vaccine-derived poliovirus; mOPV2, monovalent oral polio vaccine type 2; NID, national immunization day; sNID, supplemental national immunization day. (Source: Tegegne AA, Anyuon AN, Legge GA, et al. A circulating vaccine-derived poliovirus type 2 outbreak in a chronic conflict setting: a descriptive epidemiological study in South Sudan - 2020 to 2021. BMC Infect Dis 2023;23[1]:816. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Abbreviations: AFP, acute flaccid paralysis; NPAFP, nonpolio acute flaccid paralysis; WHO, World Health Organization.

Notes:
(1) The number of NPAFP cases per 100,000 children younger than 15 years of age per year. NPAFP cases are cases of AFP determined not to be polio on further case investigation and stool testing. The threshold of two or more NPAFP cases indicating that AFP surveillance is sufficiently sensitive to detect circulating polio is based on a background rate of AFP due to etiologies other than polioviruses.

(2) Surveillance targets are two or more NPAFP cases per 100,000 persons younger than 15 years of age per year and 80% or more of persons with AFP having two stool specimens collected within 14 days of paralysis onset, 24 or more hours apart, and received in good condition (ie, without leakage or desiccation) by a WHO-accredited laboratory via reverse cold chain (storing and transporting samples at recommended temperatures from the point of collection to the laboratory).

(3) The 2023 priority countries include the following: African Region (21): Angola, Botswana, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Democratic Republic of the Congo, Ethiopia, Equatorial Guinea, Kenya, Madagascar, Malawi, Mali, Mozambique, Niger, Nigeria, South Sudan, Tanzania, Zambia, and Zimbabwe; Eastern Mediterranean Region (five): Afghanistan, Pakistan, Somalia, Sudan, and Yemen; South-East Asia Region (one): Indonesia; and Western Pacific Region (one): Papua New Guinea.

(4) NPAFP rate is difficult to interpret when the population younger than 15 years of age is below 100,000.

(5) Dotted and dashed lines on maps represent approximate border lines for which there might not yet be full agreement.

(Source: Kishore N, Krow-Lucal E, Diop OM, et al. Surveillance to track progress toward polio eradication - worldwide, 2022-2023. MMWR Morb Mortal Wkly Rep 2024;73[13]:278-85. Public domain.)

Abbreviation: WPV1, wild poliovirus type 1. (Source: Geiger K, Stehling-Ariza T, Bigouette JP, et al. Progress toward poliomyelitis eradication - Worldwide, January 2022-December 2023. MMWR Morb Mortal Wkly Rep 2024;73[19]:441-446. Public domain.)

Data current as of May 5, 2023. Abbreviation: WPV1, wild poliovirus type 1. (Source: Lee SE, Greene SA, Burns CC, Tallis G, Wassilak SG, Bolu O. Progress toward poliomyelitis eradication - worldwide, January 2021-March 2023. MMWR Morb Mortal Wkly Rep 2023;72[19]:517-22. Public domain.)

(Source: Bammeke P, Adamu US, Bolu O, et al. Descriptive epidemiology of poliomyelitis cases due to wild poliovirus type 1 and wild poliovirus type 3 in Nigeria, 2000-2020. Pan Afr Med J 2023;45[Suppl 2]:4. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Abbreviations: AFP, acute flaccid paralysis; NPAFP, nonpolio acute flaccid paralysis; WHO, World Health Organization.

Notes:
(1) Targets: two or more NPAFP cases per 100,000 persons younger than 15 years of age per year and 80% or more of persons with AFP having two stool specimens collected within 14 or fewer days of paralysis onset and 24 or more hours apart and received in good condition (ie, without leakage or desiccation) by a WHO-accredited laboratory via reverse cold chain (storing and transporting samples at recommended temperatures from the point of collection to the laboratory).

(2) Priority countries by region in 2022 included the following: African Region (24): Angola, Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Côte d’Ivoire, Democratic Republic of the Congo, Equatorial Guinea, Ethiopia, Guinea, Guinea-Bissau, Kenya, Madagascar, Malawi, Mali, Mozambique, Niger, Nigeria, South Sudan, Tanzania, Togo, Zambia, and Zimbabwe; Eastern Mediterranean Region (7): Afghanistan, Iraq, Pakistan, Somalia, Sudan, Syria, and Yemen; South-East Asia Region (1): Burma (Myanmar); and Western Pacific Region (2): Papua New Guinea and the Philippines.

(3) NPAFP rate is difficult to interpret when the population aged younger than 15 years is less than 100,000.

(Source: Stehling-Ariza T, Wilkinson AL, Diop OM, et al. Surveillance to track progress toward poliomyelitis eradication - worldwide, 2021-2022. MMWR Morb Mortal Wkly Rep 2023;72[23]:613-20. Public domain.)

(Source: Al-Qassimi MA, Al Amad M, Al-Dar A, Al Sakaf E, Al Hadad A, Raja'a YA. Circulating vaccine-derived poliovirus type 2 outbreak and response in Yemen, 2021-2022, a retrospective descriptive analysis. BMC Infect Dis 2024;24[1]:321. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Abbreviation: cVDPV2, circulating vaccine-derived poliovirus type 2. (Source: Al-Qassimi MA, Al Amad M, Al-Dar A, Al Sakaf E, Al Hadad A, Raja'a YA. Circulating vaccine-derived poliovirus type 2 outbreak and response in Yemen, 2021-2022, a retrospective descriptive analysis. BMC Infect Dis 2024;24[1]:321. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Abbreviations: cVDPV2, circulating vaccine-derived poliovirus type 2; WPV1, wild poliovirus type 1. (Source: Mbaeyi C, Baig S, Safdar RM, et al. Progress toward poliomyelitis eradication - Pakistan, January 2022-June 2023. MMWR Morb Mortal Wkly Rep 2023;72[33]:880-5. Public domain.)

Observed incidence and median (95% CI) pre-vaccination incidence based on the main and sensitivity analyses, Sweden 1910- to 2019. Gray-shaded areas represent pre-vaccination periods. CI, confidence interval. (Source: Martin LJ, Galanis I, Lepp T, Lindstrand A. Estimated number of reported vaccine-preventable disease cases averted following the introduction of routine vaccination programs in Sweden, 1910-2019. Eur J Public Health 2023;33[6]:1188-93. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0. Modified by Dr. Douglas J Lanska to show only poliomyelitis cases with legend, whereas the original also showed curves for pertussis, measles, and mumps, and the legend was not connected with the poliomyelitis curve.)

Abbreviation: WPV1, wild poliovirus type 1. (Source: Mbaeyi C, Baig S, Safdar RM, et al. Progress toward poliomyelitis eradication - Pakistan, January 2022-June 2023. MMWR Morb Mortal Wkly Rep 2023;72[33]:880-5. Public domain.)

Major risk factors for poliovirus transmission include poor sanitation and hygiene conditions, high population density, and tropical or subtropical climate. (A) Polioviruses infect humans by the fecal-oral route. This acid-resistant virus can travel through the stomach (pH: 1–2) and reach the intestine. (B) Once in the intestine (pH: 7.3–7.7), the poliovirus (WPV or OPV) meets the commensal microbiota and the first antiviral defense, such as the mucus layer, protective peptides, immune cells expressing CD103 and KLRG1 and is able to bind the E-cadherin found at the surface of epithelial cells (Devaux and Raoult 2018; Devaux et al 2019). However, the interaction of poliovirus capsid with lipopolysaccharide of bacteria enhances virion stability and receptor attachment (Robinson et al 2014). (C) The polioviruses which manage to pass the first barrier of defense encounter a second barrier which is the intestinal epithelium, protecting the host against intruder transmigration. On this intestinal epithelium, polioviruses found their CD155 receptor on M cells. (D) Simplified model of replication cycle of polioviruses.

(Source: Devaux CA, Pontarotti P, Levasseur A, Colson P, Raoult D. Is it time to switch to a formulation other than the live attenuated poliovirus vaccine to prevent poliomyelitis? Front Public Health 2024;11:1284337. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

References cited:
Devaux CA, Mezouar S, Mege JL. The E-cadherin cleavage associated to pathogenic bacteria infections can favor bacterial invasion and transmigration, dysregulation of the immune response and cancer induction in humans. Front Microbiol 2019;10:2598.
Devaux CA, Raoult D. The microbiological memory, an epigenetic regulator governing the balance between good health and metabolic disorders. Front Microbiol 2018;9:1379.
Robinson CM, Jesudhasan PR, Pfeiffer JK. Bacterial lipopolysaccharide binding enhances virion stability and promotes environmental fitness of an enteric virus. Cell Host Microbe 2014;15(1):36-46.

The viruses were replicated either in vivo on monkey (MK) or mouse (Mo) or in vitro. The in vitro cultures used cells from different tissues (cynomolgus monkey kidney cells, rhesus monkey testicular or skin tissues). At the different stages of the selection, the strains were tested for neurovirulence in cynomolgus monkeys inoculated intraspinally, and those possessing the least residual neurovirulence were selected. Culture on chik (Chik) embryos was also used for other strains (CHAT and Cox) replicated in vivo in humans (Hu) and was used for selection of the CHAT strain. Large batches of the three types of Sabin OPVs were produced using cultures of monkey kidney cells transformed by the SV40 susceptible to poliovirus infection and replication.

Abbreviations: Hu, human; MK, monkey; Mo, mouse; OPV, oral poliovirus vaccine.

(Source: Devaux CA, Pontarotti P, Levasseur A, Colson P, Raoult D. Is it time to switch to a formulation other than the live attenuated poliovirus vaccine to prevent poliomyelitis? Front Public Health 2024;11:1284337. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(Upper panel) Mahoney virus. P1 is the precursor of the capsid proteins; P2 and P3 are the precursors of the noncapsid proteins. The genome segment from nucleotide 743 to 3,832 encodes a polyprotein precursor amino acids 1 to 1,030. Noncoding region = NCR (also designed UTR for untranslated region); nuclotide = nt.

(Middle panel) Sabin OVP1 strain. The complete nucleotide sequence of the attenuated Sabin OPV1 compared with the WPV Mahoney strain (Nomoto et al 1982) identified 57 base substitutions to be scattered all over the genome. Of these, 21 were missense mutations (red triangle) resulting in amino acid changes in some viral proteins, especially in the NH2-terminal half of the VP1 capsid protein, involved in attenuation (each mutation indicated by a red star). The location of the principal nucleotide substitutions leading to the attenuated phenotype is indicated in blue (A480G, G935U, U2438A, G2795A, and C2879U for the Sabin OPV1).

(Lower panel) Location of the principal nucleotide substitutions leading to the attenuated phenotype of Sabin OPV2 and OPV3 (the other substitutions are not shown).

Abbreviations: NCR, noncoding region; nt, nucleotide; OPV1, OPV2, OPV3, oral live-attenuated poliovirus vaccine types 1, 2, and 3; P1, the precursor of the capsid proteins; P2 and P3, precursors of the non-capsid proteins (also designed UTR for untranslated region); WPV, wild poliovirus.

(Source: Devaux CA, Pontarotti P, Levasseur A, Colson P, Raoult D. Is it time to switch to a formulation other than the live attenuated poliovirus vaccine to prevent poliomyelitis? Front Public Health 2024;11:1284337. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Reference cited:
Nomoto A, Omata T, Toyoda H, et al. Complete nucleotide sequence of the attenuated poliovirus Sabin 1 strain genome. Proc Natl Acad Sci U S A 1982;79(19):5793-7.

Data derived from WHO HQ as of February 27, 2024. Abbreviations: AFP, acute flaccid paralysis; cVDPV, circulating vaccine-derived poliovirus; WPV, wild-type poliovirus. (Source: Lopez Cavestany R, Eisenhawer M, Diop OM, Verma H, Quddus A, Mach O. The last mile in polio eradication: program challenges and perseverance. Pathogens 2024;13[4]:323. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Clinical acute flaccid paralysis (AFP) and environmental surveillance (ES) poliovirus detections are depicted. On the left, there is a per-country list of the latest detections of AFP and ES. Data source: from WHO HQ as of February 27, 2024; figure adapted from internal WHO HQ figures; map creation April 5, 2024; map produced by WHO GIS Centre for Health, DNA/DDI. Dotted and dashed lines on maps represent approximate border lines for which there may not yet be full agreement. (Source: Lopez Cavestany R, Eisenhawer M, Diop OM, Verma H, Quddus A, Mach O. The last mile in polio eradication: program challenges and perseverance. Pathogens 2024;13[4]:323. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Abbreviations: IPV, inactivated poliovirus vaccine, containing formalin-killed virus, developed by U.S. physician and virologist Jonas Salk (1914-1995) and licensed for use in 1955; OPV, oral poliovirus vaccine containing live-attenuated poliovirus, was developed by Polish-American microbiologist Albert Sabin (1906-1993). (Source: Lopez Cavestany R, Eisenhawer M, Diop OM, Verma H, Quddus A, Mach O. The last mile in polio eradication: program challenges and perseverance. Pathogens 2024;13[4]:323. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

The figure depicts the use of Sabin OPV (mOPV2 and tOPV) for outbreak response and introduction of nOPV2 in March 2021. The data are from July 1, 2016 to December 31, 2023.

Abbreviations: cVDPV2, type 2 circulating vaccine-derived type 2 monovalent oral poliovirus vaccine; tOPV, trivalent oral poliovirus vaccine; bOPV, bivalent oral poliovirus vaccine; mOPV2, type 2 monovalent oral poliovirus vaccine; nOPV2, novel type 2 oral poliovirus vaccine.

(Source: Lopez Cavestany R, Eisenhawer M, Diop OM, Verma H, Quddus A, Mach O. The last mile in polio eradication: program challenges and perseverance. Pathogens 2024;13[4]:323. Based on a figure from: Bandyopadhyay AS, Zipursky S. A novel tool to eradicate an ancient scourge: the novel oral polio vaccine type 2 story. Lancet Infect Dis 2023;23[2]:e67-71. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(A) Humoral immunity. (B) Mucosal immunity. Abbreviations: IPV, inactivated poliovirus vaccine; fIPV, fractional-dose inactivated poliovirus vaccine; mos, months; OPV, oral polio vaccine; wks, weeks; yr, year. (Source: Sutter RW, Eisenhawer M, Molodecky NA, Verma H, Okayasu H. Inactivated poliovirus vaccine: recent developments and the tortuous path to global acceptance. Pathogens 2024;13[3]:224. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Abbreviations: cVDPV2, circulating vaccine-derived poliovirus type 2; IPV, inactivated poliovirus vaccine; SIA, supplementary immunization activity. (Source: Sutter RW, Eisenhawer M, Molodecky NA, Verma H, Okayasu H. Inactivated poliovirus vaccine: recent developments and the tortuous path to global acceptance. Pathogens 2024;13[3]:224. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(Source: Data from the U.S. Centers for Disease Control and Prevention, Atlanta, Georgia. Calculations by Dr. Douglas J Lanska.)

(Source: Data from the U.S. Centers for Disease Control and Prevention, Atlanta, Georgia. Calculations by Dr. Douglas J Lanska.)

(Source: ArboNet, U.S. Centers for Disease Control and Prevention. Public domain.)

(Source: ArboNet, U.S. Centers for Disease Control and Prevention. Public domain.)

Maryland reports state-level data only; South Carolina reports state-level data only for human infections. (Source: ArboNet, U.S. Centers for Disease Control and Prevention. Public domain.)

(Source: ArboNet, U.S. Centers for Disease Control and Prevention. Public domain.)

(Source: ArboNet, U.S. Centers for Disease Control and Prevention. Public domain.)

(Source: ArboNet, U.S. Centers for Disease Control and Prevention. Public domain.)

(Source: ArboNet, U.S. Centers for Disease Control and Prevention. Public domain.)

(Source: ArboNet, U.S. Centers for Disease Control and Prevention. Public domain.)

(Source: ArboNet, U.S. Centers for Disease Control and Prevention. Public domain.)

(Source: ArboNet, U.S. Centers for Disease Control and Prevention. Public domain.)

(A) In the right eye, OCT at the level of the lesions showed recovery of the retinal pigmented epithelium and the ellipsoid zone. (B) In the left eye, OCT showed a reduction in the hyperreflective oval deposit on the retinal surface in the left eye. (Source: Valsecchi N, Veronese C, Roda M, Ciardella AP, Fontana L. Bilateral multifocal chorioretinitis as the only presentation of acute West Nile virus infection: a case report. BMC Ophthalmol 2024;24[1]:160. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Optical coherence tomography angiography at the level of the lesions in the right eye in multifocal chorioretinitis due to acute West Nile virus infection. (A) OCT en face. (B) OCTA showed diffuse capillary network attenuation in the choriocapillaris at the level of the lesions. (C and D) OCT at the level of the lesions. (Source: Valsecchi N, Veronese C, Roda M, Ciardella AP, Fontana L. Bilateral multifocal chorioretinitis as the only presentation of acute West Nile virus infection: a case report. BMC Ophthalmol 2024;24[1]:160. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(A) In the right eye, fluorescein angiography showed hyperfluorescent lesions with a linear distribution, corresponding to the hypocyanescent lesions in indocyanine green angiography (ICGA). (B) In the left eye, fundus autofluorescence showed vitreitis, whereas optical coherence tomography showed the presence of hyperreflective dots in the vitreous chamber, hyperreflective oval deposits on the retinal surface, focal alteration in the retinal pigmented epithelium and the ellipsoid zone, and granular hyperreflective specks located predominantly in the outer and inner nuclear layers. (C) In the right eye, fundus autofluorescence showed hyperautofluorescent lesions with a linear distribution, corresponding to focal alteration in the retinal pigmented epithelium and the ellipsoid zone visualized with optical coherence tomography. (D) In the left eye, fluorescein angiography showed “target” lesions with a rim of hyperfluorescence and a central spot of hypofluorescence, corresponding to focal alteration of the retinal pigmented epithelium and the ellipsoid zone. (Source: Valsecchi N, Veronese C, Roda M, Ciardella AP, Fontana L. Bilateral multifocal chorioretinitis as the only presentation of acute West Nile virus infection: a case report. BMC Ophthalmol 2024;24[1]:160. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

West Nile virus transmission cycle involves birds (amplifying hosts) and mosquitoes (vectors). Infection can spread to humans and a diverse range of vertebrates, which are generally considered incidental or “dead-end” hosts. (Source: Simonin Y. Circulation of West Nile Virus and Usutu Virus in Europe: Overview and Challenges. Viruses 2024;16[4]:599. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Immunohistochemistry performed on human central nervous tissue showing West Nile virus antigen (red) in the cytoplasm of neurons and cell processes. (Source: Schwarz ER, Long MT. Comparison of West Nile virus disease in humans and horses: exploiting similarities for enhancing syndromic surveillance. Viruses 2023;15[6]:1230. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Hematoxylin and eosin-stained section of human brain from a fatal case of West Nile virus infection demonstrating severe neuronal necrosis and dead neurons, with infiltrating glial cells and leukocytes. (Source: Schwarz ER, Long MT. Comparison of West Nile virus disease in humans and horses: exploiting similarities for enhancing syndromic surveillance. Viruses 2023;15[6]:1230. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Birds are the main reservoirs of West Nile virus, and on infection, the virus replicates to levels allowing for transmission to mosquito vectors. In horse and human infections, the viremia is too low for transmission to mosquito vectors; thus, they are dead-end hosts. Other modes of transmission in humans include horizontal transmission by organ transplantation, blood transfusion, and occupationally via sharp instruments. Vertical transmission from mother to child occurs via placental transfer and through breast milk. (Source: Schwarz ER, Long MT. Comparison of West Nile virus disease in humans and horses: exploiting similarities for enhancing syndromic surveillance. Viruses 2023;15[6]:1230. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Number of West Nile virus cases (N = 1487), vector indices, and public health responses, by epidemiologic week start date--Maricopa County, Arizona, 2021. Neuroinvasive and non-neuroinvasive cases are shown. The vector index is the estimated proportion of infected mosquitoes of a particular species in a specific area collected during weekly mosquito surveillance. The number of persons with West Nile virus each week is based on date of symptom onset; vector index data are based on date of mosquito collection, which lags from MCDPH notification date by approximately 1 to 2 weeks. Abbreviations: MCDPH = Maricopa County Department of Public Health; MCESD-VCD = Maricopa County Environmental Services Department, Vector Control Division; VI = vector index; WNV = West Nile virus. (Source: Kretschmer M, Ruberto I, Townsend J, et al. Unprecedented outbreak of West Nile virus - Maricopa County, Arizona, 2021. MMWR Morb Mortal Wkly Rep 2023;72[17]:452-7. Public domain.)

(Source: MacIntyre C, Lourens C, Mendes A, et al. West Nile virus, an underdiagnosed cause of acute fever of unknown origin and neurological disease among hospitalized patients in South Africa. Viruses 2023;15[11]:2207. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(Source: Data from the U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, and U.S. Census Bureau population estimates for July 1 of each year of the reporting period. Plot by Dr. Douglas J Lanska.)

Past and present ecological suitability estimated for each administrative unit are based on both the reconstructions of the historical climate (a) and a counterfactual baseline (b). Ecological suitability values are averaged over the estimates of 10 independent boosted regression tree (BRT) models trained on present-day data. Under factual climate conditions (a), model simulations show clear increases in West Nile virus ecological suitability in European regions, including northern Italy, the Carpathian Mountains, the lowlands in Hungary and eastern Romania, and the Aegean region in eastern Greece. (Source: Erazo D, Grant L, Ghisbain G, et al. Contribution of climate change to the spatial expansion of West Nile virus in Europe. Nat Commun 2024;15[1]:1196. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

The density of both “probable” and “confirmed” cases is shown for each administrative area for which there was at least one confirmed case before 2020. Specifically, the number of West Nile virus (WNV) cases by aggregating both “probable” and “confirmed” per km² (a) or per 100,000 people (b), either considering the NUTS3 or optimized NUTS3 administrative polygons. Nomenclature of Territorial Units for Statistics or NUTS (French: Nomenclature des unités territoriales statistiques) is a geocode standard for referencing the administrative divisions of countries for statistical purposes. The NUTS numbering refers to the size of the administrative units, with NUTS1 the most aggregated and NUTS3 the smallest, with population size of 150,000 to 800,000. Darker grey areas correspond to Switzerland and Bosnia and Herzegovina, countries that are not included in the ECDC WNV surveillance. The administrative areas of those countries were not considered when training ecological niche models. The United Kingdom is also not included in the ECDC WNV surveillance but was considered when training the models as the country has not reported any WNV cases. (Source: Erazo D, Grant L, Ghisbain G, et al. Contribution of climate change to the spatial expansion of West Nile virus in Europe. Nat Commun 2024;15[1]:1196. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(Source: Tascini C, Iantomasi R, Sbrana F, et al. MAGLIO study: epideMiological Analysis on invasive meninGococcaL disease in Italy: fOcus on hospitalization from 2015 to 2019. Intern Emerg Med 2023;18[7]:1961-9. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(Source: Tascini C, Iantomasi R, Sbrana F, et al. MAGLIO study: epideMiological Analysis on invasive meninGococcaL disease in Italy: fOcus on hospitalization from 2015 to 2019. Intern Emerg Med 2023;18[7]:1961-9. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(Source: GBD 2019 Meningitis Antimicrobial Resistance Collaborators. Global, regional, and national burden of meningitis and its aetiologies, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019. Lancet Neurol 2023;22[8]:685-711. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(Source: GBD 2019 Meningitis Antimicrobial Resistance Collaborators. Global, regional, and national burden of meningitis and its aetiologies, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019. Lancet Neurol 2023;22[8]:685-711. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(Source: GBD 2019 Meningitis Antimicrobial Resistance Collaborators. Global, regional, and national burden of meningitis and its aetiologies, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019. Lancet Neurol 2023;22[8]:685-711. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(Source: GBD 2019 Meningitis Antimicrobial Resistance Collaborators. Global, regional, and national burden of meningitis and its aetiologies, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019. Lancet Neurol 2023;22[8]:685-711. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Persons vaccinated by month and antigen during concurrent outbreaks of hepatitis A, invasive meningococcal disease, and mpox, Florida, USA, 2021 to 2022. The figure shows the number of adult persons (older than 18 years of age) vaccinated with their first dose, by month the first dose was administered. For hepatitis A, the number includes persons vaccinated with any Food and Drug Administration (FDA)-approved vaccine against hepatitis A virus. For meningococcal disease, the number includes persons vaccinated with any FDA-approved serogroup ACWY vaccine (Menveo [GlaxoSmithKline], Menactra [Sanofi Pasteur, Inc], MenQuadfi [Sanofi Pasteur, Inc]). For mpox, the number includes persons vaccinated with JYNNEOS (Bavarian Nordic). FDA, Food and Drug Administration. (Source: Doyle TJ, Gumke M, Stanek D, et al. Concurrent outbreaks of hepatitis a, invasive meningococcal disease, and mpox, Florida, USA, 2021-2022. Emerg Infect Dis 2024;30[4]:633-43. Public domain.)

Spatial distribution of outbreak-associated cases of hepatitis A and invasive meningococcal disease in an investigation of concurrent outbreaks in Florida, 2021 to 2022. (A) Locations of cases by postal (ZIP) code of patient residence; (B) detail of box from central Florida in panel A, in which more than one case of each disease were reported in the same postal code. Outside the area represented in that panel, no instances of both diseases were identified in the same postal code. Invasive meningococcal disease cases were georeferenced by postal code centroid. Small polygons are outlines of postal code areas. Light gray lines indicate county borders; dark gray lines indicate postal areas where cases were identified. (Source: Doyle TJ, Gumke M, Stanek D, et al. Concurrent outbreaks of hepatitis a, invasive meningococcal disease, and mpox, Florida, USA, 2021-2022. Emerg Infect Dis 2024;30[4]:633-43. Public domain.)

Epidemiologic curves of concurrent outbreaks of hepatitis A and invasive meningococcal disease by week of symptom onset, Florida, USA, November 1, 2021 to November 30, 2022. (A) Invasive meningococcal disease; (B) hepatitis A. The case definition for invasive meningococcal disease cases had two categories: confirmed and probable. The case definition for hepatitis A cases had three categories: confirmed, probable, and suspect. (Source: Doyle TJ, Gumke M, Stanek D, et al. Concurrent outbreaks of hepatitis a, invasive meningococcal disease, and mpox, Florida, USA, 2021-2022. Emerg Infect Dis 2024;30[4]:633-43. Public domain.)

Recommended meningococcal vaccines for persons at increased risk for meningococcal disease due to serogroups A, B, C, W, or Y and who are due for both meningococcal A, C, W, and Y vaccine and meningococcal B vaccine. Notes: (1) MenACWY products are interchangeable; the same vaccine product is recommended, but not required, for all doses. (2) Different manufacturers’ MenB vaccines are not interchangeable. (3) To determine whether MenACWY and MenB are indicated based on a person’s risk factors and timing of any previous meningococcal vaccines, clinicians should see previously published recommendations (Mbaeyi SA, Bozio CH, Duffy J, et al. Meningococcal vaccination: recommendations of the Advisory Committee on Immunization Practices, United States, 2020. MMWR Recomm Rep 2020;69[9]:1-41). (4) If MenB was received previously, but the vaccine manufacturer is not known, the series must be restarted with any licensed product to ensure completion of the series using products from a single manufacturer (Mbaeyi et al 2020). (5) If MenB-FHbp was received previously, MenACWY-TT/MenB-FHbp may be used provided the person has not received MenACWY-TT/MenB-FHbp previously or 6 or more months have passed since the previous dose of MenACWY-TT/MenB-FHbp.

Abbreviations: MenACWY = quadrivalent (serogroups A, C, W, and Y) meningococcal conjugate vaccine; MenACWY-TT/MenB-FHbp = Penbraya (Pfizer Inc) pentavalent (serogroups A, B, C, W, and Y) meningococcal vaccine; MenB-FHbp = Trumenba (Pfizer Inc) serogroup B meningococcal vaccine; MenB-4C = Bexsero (GSK) serogroup B meningococcal vaccine.

(Source: Collins JP, Crowe SJ, Ortega-Sanchez IR, et al. Use of the Pfizer pentavalent meningococcal vaccine among persons aged ≥10 years: recommendations of the Advisory Committee on Immunization Practices - United States, 2023. MMWR Morb Mortal Wkly Rep 2024;73[15]:345-50. Public domain.)

(Source: Advisory Committee on Immunization Practices, 1997. Public domain.)

(Source: Advisory Committee on Immunization Practices, 1997. Public domain.)

MRI of the head/ internal auditory canal with gadolinium demonstrated asymmetrical enhancement of the tympanic and mastoid segments of the left facial nerve and both internal auditory canals. (Source: Sheik-Ali S, Jiang Y, Nasef H, Sproson E, Tuohy O. Bilateral sequential Ramsay Hunt syndrome in an immunocompromised adult: a rare entity. Ann R Coll Surg Engl 2024;106[2]:197-9 Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Extensive vesicular eruption involving the left pinna and external auditory canal, with an associated necrotic focus in the conchal bowl and subsequent blistering. (Source: Sheik-Ali S, Jiang Y, Nasef H, Sproson E, Tuohy O. Bilateral sequential Ramsay Hunt syndrome in an immunocompromised adult: a rare entity. Ann R Coll Surg Engl 2024;106[2]:197-9 Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Symptoms presented by 10 confirmed cases during the anthrax outbreak in the Koraput district of Odisha, India, April to May 2023. (Source: Parai D, Pattnaik M, Choudhary HR, et al. Investigation of human anthrax outbreak in Koraput district of Odisha, India. Travel Med Infect Dis 2023;56:102659. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Stratification of suspected cutaneous and gastrointestinal human anthrax cases by type of anthrax and date of onset in the Koraput district of Odisha, India, April to May 2023. (A) Cutaneous-only cases. Cluster I refers to the outbreak in the Boipariguda administrative block; Cluster II refers to the outbreak in the Dashmantpur administrative block. (B) GI-only cases. (C) Cases of both cutaneous and GI anthrax. (Source: Parai D, Pattnaik M, Choudhary HR, et al. Investigation of human anthrax outbreak in Koraput district of Odisha, India. Travel Med Infect Dis 2023;56:102659. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Epidemic curve showing distribution by date of onset of suspected human anthrax cases in different administrative blocks of the Koraput district of Odisha, India, during an anthrax outbreak in April to May 2023. (A) All anthrax cases in the Koraput district. (B) Suspected anthrax cases in the Boipariguda block. (C) Suspected anthrax cases in the Dashmantpur block. (D) Suspected anthrax cases in the Semiliguda block. (Source: Parai D, Pattnaik M, Choudhary HR, et al. Investigation of human anthrax outbreak in Koraput district of Odisha, India. Travel Med Infect Dis 2023;56:102659. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Screening tool to identify potential anthrax meningitis cases by presenting signs and symptoms after a mass casualty event when diagnostic capability is limited.

Abbreviations: CSF = cerebrospinal fluid; CT = computed tomography

(Source: Bower WA, Yu Y, Person MK, et al. CDC Guidelines for the Prevention and Treatment of Anthrax, 2023. MMWR Recomm Rep 2023;72(6):1-47. Adapted from Figure 2 in: Binney S, Person MK, Traxler RM, Cook R, Bower WA, Hendricks K. Algorithms for the identification of anthrax meningitis during a mass casualty event based on a systematic review of systemic anthrax from 1880 through 2018. Clin Infect Dis 2022;75(Suppl 3):S468-77. Public domain.)

MRI repeated on day 7 shows partial resolution of the pontine lesions, but now there are confluent ring-enhancing lesions in the medulla with surrounding edema. There is a little hemorrhage seen within the medullary lesions on GRE sequence. (Contributed by Dr. Sudhir Kothari.)

MRI repeated on day 7 shows partial resolution of the pontine lesions, but now there are confluent ring-enhancing lesions in the medulla with surrounding edema. There is a little hemorrhage seen within the medullary lesions on GRE sequence. (Contributed by Dr. Sudhir Kothari.)

Brain MRI on day 3 shows a lesion on FLAIR sequence, mainly in the posterior left pons, extending down to the medulla. There is slight enhancement of the left trigeminal nerve as it exited the pons. (Contributed by Dr. Sudhir Kothari.)

Brain MRI on day 3 shows a lesion on FLAIR sequence, mainly in the posterior left pons, extending down to the medulla. There is slight enhancement of the left trigeminal nerve as it exited the pons. (Contributed by Dr. Sudhir Kothari.)

(Source: Archivio Università di Sassari. Public domain.)

Sir Thomas Morison Legge was a British physician and the first medical inspector of factories. (Source: Photograph by British professional photographer Graystone Bird [1862-1943]. Courtesy of the Wellcome Trust, London. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0/deed.en.)

(Source: U.S. Army, October 28, 2003. Public domain.)

Photomicrograph of a tissue specimen harvested from the bronchus of a deceased 60-year-old man, showing cytoarchitectural changes of inhalation anthrax (H&E). (Source: CDC. Photograph by Sidney J Brodsky, 1966. Public Health Image Library, image number 15242. Public domain.)

Posteroanterior chest x-ray taken 4 months after onset of anthrax in a 46-year-old man. Note the widened mediastinum and bilateral pulmonary effusion. The patient had worked for 2 years as a card tender in a goat hair processing mill and acquired "woolsorter disease," an occupational form of inhalation anthrax. (Source: CDC. Photograph by Arthur E Kaye, 1972. Public Health Image Library, image number 5146. Public domain.)

Photomicrograph of a small-intestine tissue sample (H&E, x240) revealing submucosal hemorrhage in a fatal human case of anthrax. (Source: CDC. Photograph by Dr. Marshall Fox, 1976. Public Health Image Library, image number 4629. Public domain.)

Photomicrograph of a small-intestine tissue sample (H&E, x240) revealing submucosal hemorrhage in a fatal human case of anthrax. (Source: CDC. Photograph by Dr. Marshall Fox, 1976. Public Health Image Library, image number 4628. Public domain.)

Photomicrograph of meningeal tissue sample (H&E) reveals an infection due to Bacillus anthracis bacteria. (Source: CDC. Photograph by S Benesky, 1966. Public Health Image Library, image number 4627. Public domain.)

Coronal brain section through the ventricles, revealing an interventricular hemorrhage, from a fatal human case of anthrax. (Source: CDC, 1966. Public Health Image Library, image number 3376. Public domain.)

Photomicrograph of a lymph node tissue sample (H&E), harvested at autopsy, from a 33-year-old patient with inhalation anthrax. Histopathologic findings of tissue necrosis. (Source: CDC. Photograph by S Benesky, 1966. Public Health Image Library, image number 1808. Public domain.)

Posteroanterior chest x-ray on the fourth day of illness from a fatal case of inhalation anthrax. Note the widened mediastinum and pleural effusion. (Source: CDC. Public Health Image Library, image number 1795. Public domain.)

Photomicrograph of a meningeal tissue sample demonstrating darkly stained, rod-shaped Bacillus anthracis bacteria from a fatal human case of inhalation anthrax. (Source: CDC. Photograph by Dr. LaForce, 1967. Public Health Image Library, image number 1791. Public domain.)

Photomicrograph showing histopathologic changes in a lung tissue sample from a fatal human case of inhalation anthrax (Brown and Brenn (B&B) stain, x500). Note the darkly stained, rod-shaped Bacillus anthracis bacteria. (Source: CDC. Photograph by Dr. LaForce, 1967. Public Health Image Library, image number 1789. Public domain.)

Photomicrograph showing histopathologic changes in lung tissue harvested from a fatal human case of inhalation anthrax (x50). (Source: CDC. Photograph by Dr. LaForce, 1967. Public Health Image Library, image number 1790. Public domain.)

Photomicrograph showing hemorrhagic changes in a meningeal tissue sample in a fatal human case of inhalation anthrax (x500). (Source: CDC. Photograph by Dr. LaForce, 1967. Public Health Image Library, image number 1786. Public domain.)

Photomicrograph showing hemorrhagic changes in a meningeal tissue sample in a fatal human case of inhalation anthrax (x125). (Source: CDC. Photograph by Dr. LaForce, 1967. Public Health Image Library, image number 1787. Public domain.)

Photomicrograph showing histopathologic details in a fatal human case of hemorrhagic meningitis due to anthrax. Note the rod-shaped, darkly stained Bacillus anthracis bacteria. (Source: CDC. Photograph by Dr. Marshall Fox, 1976. Public Health Image Library, image number 1783. Public domain.)

Photomicrograph of a small intestine tissue sample (H&E, x96) revealing marked mucosal and submucosal hemorrhage with accompanying arteriolar degeneration in a fatal human case of anthrax. (Source: CDC. Photograph by Dr. Marshall Fox, 1976. Public Health Image Library, image number 722. Public domain.)

Investigation of cutaneous anthrax in a ranch hand in Texas c2001 revealed an anthrax epizootic among animals imported to Texas ranches for exotic animal sport hunting. In this photograph, a CDC physician was performing a lymph node biopsy on a dead aoudad. The animal had died less than 24 hours earlier of a hemorrhagic diathesis consistent with anthrax, and this biopsy confirmed the diagnosis. (Source: CDC/CDC Connects. Photograph by Jane Kelly MD. Public Health Image Library, image number 22487. Public domain.)

This 2000 photograph depicted a sign displayed in Gorakhpur, India, which advertised a Pulse Polio Vaccination Program that had been scheduled to take place on February 27, 2000, the main purpose of which was to vaccinate children up to 5 years of age against polio. (Source: CDC/Chris Zahniser BSN RN MPH. Zahniser was a "Stop Transmission of Polio" (STOP) team member and photographer, who was assigned to the state of Uttar Pradesh in northern India. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Scene at a Birmingham, Alabama airport, where the Alabama National Guard was preparing to fly polio vaccine to Haleyville during the polio epidemic of 1963. (Source: CDC/Mr. Stafford Smith, 1963. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Images like this were used to encourage individuals to receive polio vaccinations, which were made available in April 1955. (Source: CDC. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

A young girl receiving her Salk polio vaccination in her left upper arm. The girl was among local residents who had lined up at this mobile polio vaccination clinic. This photograph was taken in 1963, when the U.S. was shifting from the killed-virus Salk vaccine to the oral attenuated Sabin vaccine. (Source: CDC, 1963. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

A Pakistani Field Epidemiology Training Program (FETP) 2nd cohort resident, (Dr. Muhammad Dawood Kasi) administering oral polio vaccine (OPV) to unvaccinated children in the union council locality of Kharotabad, Balochistan, Pakistan, during the July 2011, polio campaign. The FETP trains workers on the ground to help countries build sustainable capacity for detecting and responding to health threats. The program develops in-country expertise so that disease outbreaks can be detected locally and prevented from spreading. (Source: CDC/Tamkeen Ghafoor, Pakistan. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

A Somali mother holding her child steady, while a "Stop Transmission of Polio" (STOP) worker administered the oral polio vaccine to the young infant. WHO and UNICEF, working in conjunction with national Ministries of Health, request skilled short-term consultants, who can provide field support to immunization programs. STOP participants are descendants of the "smallpox warriors" of the 1970s. (Source: CDC/Shurram Shahzad, Somalia, 2014. Stop Transmission of Polio (STOP) Program. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

A young girl receiving her polio immunization by way of an orally administered sugar cube at a Dekalb County, Georgia, well-child clinic. (Source: CDC/Meredith Hickson, 1977. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

A young child being supported by a healthcare worker atop a clinic table. Although the child looks to be old enough to be able to walk on his own, after having acquired poliomyelitis, the resulting lower limb paralysis prevented him from supporting his own weight. (Source: PAHO/WHO, 1989. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

The child pictured here in this 2000 photograph, held by her father, had been diagnosed with acute flaccid paralysis, 2 months prior to being photographed. The father was bringing his child to a physician for a follow-up evaluation. Since its inception in the fall of 1998, the "Stop Transmission of Polio" (STOP) immunization initiative teams have worked in over 50 countries. In the first years of the program, most STOP team members worked primarily to bolster acute flaccid paralysis surveillance, support National Immunization Days, and conduct polio case investigation and follow-up. (Source: CDC/Chris Zahniser BSN RN MPH, 2000. Zahniser was a Stop Transmission of Polio [STOP] team member and photographer, who was assigned to the state of Uttar Pradesh in northern India. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

This 1963 poster featured what at that time, was the Communicable Disease Center’s (CDC) national symbol of public health, the "Wellbee," who was reminding the public to "be well, be clean, WASH YOUR HANDS". CDC used Wellbee in a comprehensive marketing campaign that included newspapers, posters, leaflets, radio, and television, as well as personal appearances at public health events. Wellbee’s first assignment was to sponsor the Sabin type II oral polio vaccine (OPV) campaigns across the United States. Later, Wellbee’s character was incorporated into other health promotion campaigns. CDC's name changed in 1970 from the Communicable Disease Center to the Center for Disease Control, and in 1992 to the Centers for Disease Control and Prevention. (Source: CDC/Mary Hilpertshauser, 1963. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

This 1963 poster featured what at that time, was the Communicable Disease Center’s (CDC) national symbol of public health, the "Wellbee," who was reminding the public to "be well, be clean, WASH YOUR HANDS." CDC used Wellbee in a comprehensive marketing campaign that included newspapers, posters, leaflets, radio, and television, as well as personal appearances at public health events. Wellbee’s first assignment was to sponsor the Sabin type II oral polio vaccine (OPV) campaigns across the United States. Later, Wellbee’s character was incorporated into other health promotion campaigns. CDC's name changed in 1970 from the Communicable Disease Center to the Center for Disease Control, and in 1992 to the Centers for Disease Control and Prevention. (Source: CDC/Mary Hilpertshauser, 1963. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

This 1964 poster featured what at that time, was the Communicable Disease Center’s (CDC) national symbol of public health, the "Wellbee," who was reminding the public to "be well, be clean, WASH YOUR HANDS." CDC used Wellbee in a comprehensive marketing campaign that included newspapers, posters, leaflets, radio, and television, as well as personal appearances at public health events. Wellbee’s first assignment was to sponsor the Sabin type II oral polio vaccine (OPV) campaigns across the United States. Later, Wellbee’s character was incorporated into other health promotion campaigns. CDC's name changed in 1970 from the Communicable Disease Center to the Center for Disease Control, and in 1992 to the Centers for Disease Control and Prevention. (Source: CDC/Mary Hilpertshauser, 1964. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Dr. Joseph Oren, Chief of the CDC Poliomyelitis Surveillance Unit, was examining the child, who was displaying signs of respiratory weakness. A suction machine was being used, in conjunction with a tracheostomy tube to help in suctioning sputum build-up from the lungs. (Source: CDC, 1960. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Aerial view of a long line of people waiting for their polio vaccinations. The line surrounded the city auditorium in San Antonio, Texas. (Source: CDC/Mr. Stafford Smith, 1962. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Physical therapist assisting two polio-stricken children that were holding on to a handrail, while they exercised their lower limbs, by keeping a beach ball suspended between their upper bodies. (Source: CDC/Charles Farmer, 1963. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Scanning electron microscopic (SEM) image depicted a number of round, polio virions, or virus particles, scattered on a background plane. (Source: CDC. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Latin-American nurse performing a neurologic examination on a boy with residua of poliomyelitis. Note the severe atrophy of muscles in both lower legs and the callouses over the knees and possible effusion of the knee joint, indicating that the boy ambulated by crawling. (Source: PAHO/WHO, 1989. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

This mother was cradling her child, as he received an oral polio vaccine, which would prevent the baby from acquiring the highly infectious disease poliomyelitis (polio), caused by the poliovirus. Beginning in 1988, the efforts of the World Health Organization (WHO), Rotary International, the U.S. Centers for Disease Control and Prevention (CDC), and UNICEF, through the Global Polio Eradication Initiative, led to the realistic possibility of global eradication of this viral disease. (Source: PAHO/WHO, 1989. This image is from the 1989 Pan American Health Organization (PAHO) Polio Eradication Field Guide. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Healthcare worker supporting an infant, who was at an age when he should have been able to walk, however, poliomyelitis caused lower limb weakness that made him unable to support his own weight. (Source: PAHO/WHO, 1989. Unidentified Latin-American country. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Photomicrograph of a spinal cord tissue sample at higher magnification in the region of the anterior horn, revealing polio type III degenerative changes. (Source: CDC/Dr. Karp, Emory University, 1964. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Photomicrograph of a spinal cord tissue sample at low magnification in the region of the anterior horn, revealing polio type III degenerative changes. (Source: CDC/Dr. Karp, Emory University, 1964. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

(Source: CDC, 1961. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Transmission electron microscopic image depicting numerous, round, poliovirus type-1 virions, which measure 20-30nm in diameter, and exhibit icosahedral symmetry. (Source: CDC/ Dr. Joseph J. Esposito; F. A. Murphy, 1971. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

Two workers standing beside a cart loaded with boxes containing poliovirus vaccine, produced at the time by the Wyeth pharmaceutical company. (Source: CDC/ Mr. Stafford Smith, 1963. U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

(1) First, poliovirus binds to the cell surface macromolecule CD155, which functions as the receptor. (2) Uncoating the viral RNA is mediated by receptor-dependent destabilization of the virus capsid. (3) Cleavage of the viral protein VPg is performed by a cellular phosphodiesterase, and translation of the viral RNA occurs by a cap-independent (IRES-mediated) mechanism. (4) Proteolytic processing of the viral polyprotein yields mature structural and non-structural proteins. (5) The positive-sense RNA serves as the template for complementary negative-strand synthesis, thereby producing a double-stranded RNA (replicative form, RF). (6) Initiation of many positive strands from a single negative strand produces the partially single-stranded replicative intermediate (RI). (7) The newly synthesized positive-sense RNA molecules can either serve as templates for translation or (8) associate with capsid precursors to undergo encapsidation and induce the maturation cleavage of VP0, which ultimately generates progeny virions. (9) Lysis of the infected cell results in release of infectious progeny virions. (Source: De Jesus NH. Epidemics to eradication: the modern history of poliomyelitis. Virol J 2007;4:70. Creative Commons Attribution [CC BY] license, creativecommons.org/licenses/by/2.0.)

This genomic region has been divided into six domains (I to VI), of which domain I constitutes the cloverleaf and the remaining domains comprise the internal ribosome entry site (IRES). Spacer sequences without complex secondary structure exist between the cloverleaf and the IRES (nt 89-123) and between the IRES and the initiation codon (nt 620-742). Mutations in the 5'NTR of the Sabin poliovirus type 1, 2, and 3 vaccine strains localizing to nucleotides 480 (A to G), 481 (A to G), and 472 (C to U), respectively (each denoted by a star), confer attenuation in the CNS and deficient replication in neuroblastoma cells as well as reduced viral RNA translation efficiency. (Source: De Jesus NH. Epidemics to eradication: the modern history of poliomyelitis. Virol J 2007;4:70. Creative Commons Attribution [CC BY] license, creativecommons.org/licenses/by/2.0.)

After binding to cell-surface receptors, poliovirus (160S) undergoes conformational changes of the capsid to the 135S form. The 135S particles are then internalized by an actin- and tyrosine kinase-dependent, but clathrin- and caveolin-independent, mechanism. The release of the viral genome takes place only after internalization from an endocytotic compartment localized within 100-200 nm of the plasma membrane. On release of the RNA genome, the empty capsid (80S) is transported away along microtubules. (Source: Brandenburg B, Lee LY, Lakadamyali M, Rust MJ, Zhuang X, Hogle JM. Imaging poliovirus entry in live cells. PLoS Biol 2007;5[7]:e183. Creative Commons Attribution [CC BY] license, creativecommons.org/licenses/by/2.0.)

This transmission electron microscopic image reveals ultrastructural features exhibited by numerous icosahedral-shaped poliovirus particles. (Source: CDC/ Dr. Fred Murphy, Sylvia Whitfield (1975). U.S. Centers for Disease Control and Prevention, Public Health Image Library. Public domain.)

The poliovirus genome consists of a single-stranded, positive-sense polarity RNA molecule, which encodes a single polyprotein. The 5' non-translated region (NTR) harbors two functional domains, the cloverleaf and the internal ribosome entry site (IRES), and is covalently linked to the viral protein VPg. The 3'NTR is polyadenylated. (Source: De Jesus NH. Epidemics to eradication: the modern history of poliomyelitis. Virol J 2007;4:70. Creative Commons Attribution License [CC BY], creativecommons.org/licenses/by/2.0.)

Sullivan (A), Orange (B), Rockland (C), Kings and Queens (D), and Nassau (E) counties, New York. Abbreviation: PV2 = poliovirus type 2. Sampling sites are sewersheds defined as the community area served by a wastewater collection system. Sub-sewersheds are upstream sampling locations within a larger sewershed. In July 2022, paralytic poliomyelitis resulting from infection with vaccine-derived PV2 was confirmed in an unvaccinated adult resident of Rockland County, New York. A single large-volume sample from a sub-sewershed serving parts of Kings and Queens counties tested positive for the PV2 genetically linked to the virus isolated from the patient. (Source: Ryerson AB, Lang D, Alazawi MA, et al. Wastewater testing and detection of poliovirus type 2 genetically linked to virus isolated from a paralytic polio case - New York, March 9-October 11, 2022. MMWR Morb Mortal Wkly Rep 2022;71[44]:1418-24. Public domain.)

Wastewater polio test results, by jurisdiction (N = 1,053)--13 counties in New York and New York City, March 9-October 11, 2022. Abbreviation: PV2 = poliovirus type 2. Sampling sites are sewersheds defined as the community area served by a wastewater collection system. Testing was conducted to determine if a sample was negative or positive for PV2, and if positive for PV2, whether the PV2 was genetically linked to an unvaccinated paralytic poliomyelitis patient from Rockland County, New York identified in July 2022. Some samples had sequencing insufficient to determine relation to the Rockland County patient (ie, linkage to patient unknown). Indeterminate results are excluded from this figure. Indeterminate results include those from samples that tested positive using real-time reverse transcription polymerase chain reaction but not enough viral material was available to complete sequencing. Specimens pending sequencing results are also excluded. Number of samples in each jurisdiction include New York City (408) and the following New York counties: Rockland (124), Putnam (20), Orange (280), Nassau (85), Sullivan (21), Westchester (83), Suffolk (14), and Ulster (18). (Source: Ryerson AB, Lang D, Alazawi MA, et al. Wastewater testing and detection of poliovirus type 2 genetically linked to virus isolated from a paralytic polio case - New York, March 9-October 11, 2022. MMWR Morb Mortal Wkly Rep 2022;71[44]:1418-24. Public domain.)

cVDPVs are genetically linked VDPV2 isolates for which there is evidence of person-to-person transmission in the community. Total cases by period: January-June 2021 = one WPV1 and 42 cVDPV2, July-December 2021 = three WPV1 and one cVDPV2, and January-September 2022 = two WPV1 and zero cVDPV2. Abbreviations: cVDPV2 = circulating vaccine-derived poliovirus type 2; WPV1 = wild poliovirus type 1. (Source: Mohamed A, Akbar IE, Chaudhury S, et al. Progress toward poliomyelitis eradication--Afghanistan, January 2021-September 2022. MMWR Morb Mortal Wkly Rep 2022;71[49]:1541-6. Public domain.)

The number of cases of WPV1 and cVDPV2 were 90 and 351, respectively. cVDPVs are genetically linked VDPV2 isolates for which there is evidence of person-to-person transmission in the community. Abbreviations: cVDPV2 = circulating vaccine-derived poliovirus type 2; WPV1 = wild poliovirus type 1. (Source: Mohamed A, Akbar IE, Chaudhury S, et al. Progress toward poliomyelitis eradication--Afghanistan, January 2021-September 2022. MMWR Morb Mortal Wkly Rep 2022;71[49]:1541-6. Public domain.)

Abbreviations: cVDPV2 = circulating vaccine-derived poliovirus type 2; WPV1 = wild poliovirus type 1. (Source: Mbaeyi C, Baig S, Safdar MR, et al. Progress toward poliomyelitis eradication--Pakistan, January 2021-July 2022. MMWR Morb Mortal Wkly Rep 2022;71[42]:1313-8. Public domain.)

Abbreviations: cVDPV2 = circulating vaccine-derived poliovirus type 2; WPV1 = wild poliovirus type 1. (Source: Mbaeyi C, Baig S, Safdar MR, et al. Progress toward poliomyelitis eradication--Pakistan, January 2021-July 2022. MMWR Morb Mortal Wkly Rep 2022;71[42]:1313-8. Public domain.)

Abbreviation: WPV1 = wild poliovirus type 1. (Source: Lee SE, Greene SA, Burns CC, Tallis G, Wassilak SG, Bolu O. Progress toward poliomyelitis eradication--worldwide, January 2021-March 2023. MMWR Morb Mortal Wkly Rep 2023;72[19]:517-22. Public domain.)

The 3D MRI rendering shows a tick (arrow) on the surface of the head. (Source: Sarwar Z, Osborne AF, Shah C, Rathore MH. Neuroimaging in tick paralysis: looking outside the box. Infect Dis Rep 2022;14(6):837-40. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Sagittal T1-weighted MRI of the brain shows a tick in the occipital region (arrow). (Source: Sarwar Z, Osborne AF, Shah C, Rathore MH. Neuroimaging in tick paralysis: looking outside the box. Infect Dis Rep 2022;14(6):837-40. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Axial T1-weighted MRI of the brain at the level of the medulla shows a normal appearance of the medulla and the cerebellum. However, on closer inspection, there is a small, isointense area (arrow) seen attached to the skin in the occipital region on the right side. (Source: Sarwar Z, Osborne AF, Shah C, Rathore MH. Neuroimaging in tick paralysis: looking outside the box. Infect Dis Rep 2022;14(6):837-40. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

(Source: Sarwar Z, Osborne AF, Shah C, Rathore MH. Neuroimaging in tick paralysis: looking outside the box. Infect Dis Rep 2022;14(6):837-40. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0. Image cropped from original.)

The blink reflex test reveals absent responses of ipsilateral R1 and R2 and contralateral R2 at stimulation of the right supraorbital nerve. (Source: Hwang YS, Kim YS, Shin BS, Kang HG. Two cases of Ramsay-Hunt syndrome following varicella zoster viral meningitis in young immunocompetent men: case reports. BMC Neurol 2023;23[1]:43. Creative Commons Attribution 4.0 International [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0.)

The blink reflex test reveals absent responses of ipsilateral R1 and R2 and contralateral R2 at stimulation of the right supraorbital nerve. (Source: Hwang YS, Kim YS, Shin BS, Kang HG. Two cases of Ramsay-Hunt syndrome following varicella zoster viral meningitis in young immunocompetent men: case reports. BMC Neurol 2023;23[1]:43. Creative Commons Attribution 4.0 International [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Internal auditory canal (IAC) MRI image of a patient with herpes zoster oticus. The post-contrast 3D T1-weighted image shows contrast enhancement in the left vestibulocochlear nerve (small arrow) and the dura of the left IAC (large arrow). (Source: Lee J, Choi JW, Kim CH. Features of audio-vestibular deficit and 3D-FLAIR temporal bone MRI in patients with herpes zoster oticus. Viruses 2022;14[11]:2568. Creative Commons Attribution 4.0 International [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Internal auditory canal MRI image of a patient with herpes zoster oticus. The post-contrast 3D T1-weighted image shows that the labyrinthine segment of the left facial nerve is enhanced (arrow). (Source: Lee J, Choi JW, Kim CH. Features of audio-vestibular deficit and 3D-FLAIR temporal bone MRI in patients with herpes zoster oticus. Viruses 2022;14[11]:2568. Creative Commons Attribution 4.0 International [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Contrast‐enhanced T1‐weighted MRI of the brain showing enhancement in the right facial nerve (white arrows). (Source: Hwang YS, Kim YS, Shin BS, Kang HG. Two cases of Ramsay-Hunt syndrome following varicella zoster viral meningitis in young immunocompetent men: case reports. BMC Neurol 2023;23[1]:43. Creative Commons Attribution 4.0 International [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0.)

The facial nerve conduction study reveals a prolonged terminal latency and reduced compound muscle action potential amplitude upon direct stimulation of the right facial nerve. NCV = nerve conduction velocity. (Source: Hwang YS, Kim YS, Shin BS, Kang HG. Two cases of Ramsay-Hunt syndrome following varicella zoster viral meningitis in young immunocompetent men: case reports. BMC Neurol 2023;23[1]:43. Creative Commons Attribution 4.0 International [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Pure-tone audiometry revealing both increased air and bone conduction thresholds without an air-bone gap in the right ear, consistent with predominantly high-frequency sensorineural hearing loss. (Source: Hwang YS, Kim YS, Shin BS, Kang HG. Two cases of Ramsay-Hunt syndrome following varicella zoster viral meningitis in young immunocompetent men: case reports. BMC Neurol 2023;23[1]:43. Creative Commons Attribution 4.0 International [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Vesicles noted along the medial aspect of the antihelix of the right ear (arrow). (Source: Gillette BT, Heilbronn CM. A rare case of vocal cord paralysis in the setting of Ramsay Hunt syndrome. Cureus 2023;15[3]:e36027. Creative Commons Attribution [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Initial onset of Ramsay Hunt syndrome. Right facial palsy presented as an asymmetric mouth and incomplete closure of the right eye. The patient received a Grade V score on the House-Brackmann Facial Paralysis Scale. (Source: Chou CC, Lo YT, Su HC, Chang CM. Fear of falling as a potential complication of Ramsay Hunt syndrome in older adults: a case report. BMC Geriatr 2022;22[1]:901. Creative Commons Attribution 4.0 International [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0. The image was cropped from the original.)

Pure-tone audiogram showing right-sided sensorineural hearing loss of 43 dB PTA (pure-tone average) in a 42-year-old woman with herpes zoster oticus, delayed facial nerve palsy, and cranial polyneuropathy. (Source: Al-Ani RM. Ramsay Hunt syndrome with cranial polyneuropathy and delayed facial nerve palsy: a case report. Cureus 2022;14[7]:e27434. Creative Commons Attribution 4.0 International [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Right peripheral facial nerve paralysis with flattening of the nasolabial fold, drop of the oral angle, and reduced wrinkles on the forehead in a 42-year-old woman with herpes zoster oticus, delayed facial nerve palsy, and cranial polyneuropathy. (Source: Al-Ani RM. Ramsay Hunt syndrome with cranial polyneuropathy and delayed facial nerve palsy: a case report. Cureus 2022;14[7]:e27434. Creative Commons Attribution 4.0 International [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Vesicular eruption of the right auricle (A), external auditory canal, and tympanic membrane (B) in a 42-year-old woman with herpes zoster oticus, delayed facial nerve palsy, and cranial polyneuropathy. (Source: Al-Ani RM. Ramsay Hunt syndrome with cranial polyneuropathy and delayed facial nerve palsy: a case report. Cureus 2022;14[7]:e27434. Creative Commons Attribution 4.0 International [CC-BY 4.0] license, creativecommons.org/licenses/by/4.0.)

If a polio patient's diaphragm was compromised, the early treatment was use of the iron lung, a form of negative pressure ventilator. (Photo ID: NPC 3631. Source collection: OHA 250: New Contributed Photographs. Repository: National Museum of Health and Medicine, Otis Historical Archives.)

An Emerson Respirator, also known as an iron lung, was a machine that enabled a person to breathe on their own when muscle control had been lost (often due to poliomyelitis). It used negative pressure ventilation to induce inhalation. (Photo ID: NCP 4145. Source Collection: OHA 250: New Contributed Photographs Collection. Repository: National Museum of Health and Medicine, Otis Historic Archives. Creative Commons Attribution 2.0 Generic License [CC BY 2.0], https://creativecommons.org/licenses/by/2.0.)

(Creator: U.S. Air Force. File name: 244001_1370. Citation: Mayor John F Collins records, Collection #0244.001, City of Boston Archives, Boston. Creative Commons Attribution 2.0 Generic License [CC BY 2.0], https://creativecommons.org/licenses/by/2.0.)

(Photo by Don Pinder. Courtesy of the Florida Keys Public Library. Creative Commons Attribution 2.0 Generic License [CC BY 2.0], https://creativecommons.org/licenses/by/2.0.)

(Source: Oakenroad. Creative Commons Attribution 2.0 Generic License [CC BY 2.0], https://creativecommons.org/licenses/by/2.0.)

Late stage, extreme atrophy of the lower portion of the trunk, the pelvic region, and the legs; marked pes varus, right side. (Source: Bing R. A textbook of nervous diseases for students and practising physicians in thirty lectures. Authorized translation by Charles L Allen. New York: Rebman Co, 1921.)

(Source: Bing R. A textbook of nervous diseases for students and practising physicians in thirty lectures. Authorized translation by Charles L Allen. New York: Rebman Co, 1921.)

(Source: Bing R. A textbook of nervous diseases for students and practising physicians in thirty lectures. Authorized translation by Charles L Allen. New York: Rebman Co, 1921.)

The images are from Plate 539 in Muybridge’s Animal Locomotion (Muybridge E. Animal locomotion: an electrophotographic investigation of consecutive phases of animal movements, 1872-1885. Philadelphia: University of Pennsylvania, 1887). The boy was photographed by English-American photographer Eadweard Muybridge (1830-1904) and American neurologist Francis Xavier Dercum (1856-1931) in 1885. (Public domain. Courtesy of the Boston Public Library and available either through Wikimedia Commons or Digital Commonwealth Massachusetts Collections Online.)

For details, see:
Lanska DJ. The Dercum-Muybridge collaboration for sequential photography of neurologic disorders. Neurology 2013;81:1550-4.
Lanska DJ. The Dercum-Muybridge collaboration and the study of pathologic gaits using sequential photography. J Hist Neurosci 2016a;25:23-38.
Lanska DJ. A human quadrupedal gait following poliomyelitis: From the Dercum-Muybridge collaboration (1885). Neurology 2016b;86:872-6.

Note the accentuated anterior pelvic tilt and lumbar lordosis producing a swayback posture, the marked atrophy of the leg muscles, and the back-kneeing (genu recurvatum). The images are from Plate 539 in Muybridge’s Animal Locomotion (Muybridge E. Animal locomotion: an electrophotographic investigation of consecutive phases of animal movements, 1872-1885. Philadelphia: University of Pennsylvania, 1887). The boy was photographed by English-American photographer Eadweard Muybridge (1830-1904) and Francis Xavier Dercum (1856-1931) in 1885. (Public domain. Courtesy of the Boston Public Library and available either through Wikimedia Commons or Digital Commonwealth Massachusetts Collections Online.)

For details, see:
Lanska DJ. The Dercum-Muybridge collaboration for sequential photography of neurologic disorders. Neurology 2013;81:1550-4.
Lanska DJ. The Dercum-Muybridge collaboration and the study of pathologic gaits using sequential photography. J Hist Neurosci 2016a;25:23-38.
Lanska DJ. A human quadrupedal gait following poliomyelitis: From the Dercum-Muybridge collaboration (1885). Neurology 2016b;86:872-6.

Case of Hans Spitzy (1912). "Handwalker" girl, 7 years of age. All of the muscles in both legs, except the iliopsoas of each side, are paralyzed. The child can get around only by crawling. Duration of paralysis was 5 years. (Source: Spitzy H. Surgical measures in diseases of nervous origin. [Translated by Carl G Leo-Wolf]. In: Pfaundler M, Schlossmann A, editors. The diseases of children: a work for the practising physician. [English translation edited by Henry LK Shaw and Linnæus la Pétra]. Volume 5. Philadelphia and London: JB Lippincott Co, 1912:322-3.)

Case of Austrian orthopedist Hans Spitzy (1912). "The patient can walk a little in erect posture after arthrodesis in both knees. To prevent post-operative curvature [of the legs] she wears celluloid braces (for 2 years)." (Source: Spitzy H. Surgical measures in diseases of nervous origin. [Translated by Carl G Leo-Wolf]. In: Pfaundler M, Schlossmann A, editors. The diseases of children: a work for the practising physician. [English translation edited by Henry LK Shaw and Linnæus la Pétra]. Volume 5. Philadelphia and London: JB Lippincott Co, 1912:322-3.)

Case of German orthopedist Oskar Vulpius (1915). Boy using a hands-and-knees crawl: infantile spinal paralysis (handwalker) (observation of Professor O Vulpius, Heidelberg). (Source: Ibrahim J. Poliomyelitis anterior acuta [acute spinal infantile paralysis]. In: Burr CW, editor. Text-book on nervous diseases. Philadelphia: P Blakiston’s Son & Co, 1915:793-810. See also: Lanska DJ. A human quadrupedal gait following poliomyelitis: From the Dercum-Muybridge collaboration [1885]. Neurology 2016;86:872-6.)

Case of Swiss neurologist Robert Bing (1921). Boy using a hands-and-feet bear crawl: infantile spinal paralysis. So-called "handwalker" as a result of severe dorsal and lumbar poliomyelitis. Note the marked atrophy in the pelvic girdle and leg muscles. (Source: Bing R. A textbook of nervous diseases for students and practising physicians in thirty lectures. Authorized translation by Charles L Allen. New York: Rebman Co, 1921. See also: Lanska DJ. A human quadrupedal gait following poliomyelitis: From the Dercum-Muybridge collaboration [1885]. Neurology 2016;86:872-6.)

Case of Austrian pediatrician Heinrich Lehndorff (1908). Poliomyelitis in a 7-year-old child. Severe paralysis of both legs. Flexion contracture in the hip joint, severe lordosis of the lumbar spine. "Hand walkers." [Case] of Dr. H[einrich] Lehndorff in the Carolinen Children's Hospital in Vienna. Note also the accentuated anterior pelvic tilt, which, in combination with the accentuated lumbar lordosis, produces a swayback posture; the marked atrophy of the leg muscles; and the back-kneeing (genu recurvatum). (Sources: Zappert J. Die Epidemie der Poliomyelitis acuta epidemica. [Heine-Medinsche. Krankheit] in Wien und Nieder-Oester reich. Jahre 1908. Oppenheim H. Text-book of nervous disease for physicians and students: authorized translation by Alexander Bruce. 5th edition. Edinburgh: Otto Schultze & Co, 1911;1:209. See also: Lanska DJ. A human quadrupedal gait following poliomyelitis: From the Dercum-Muybridge collaboration [1885]. Neurology 2016;86:872-6.)

Case of Austrian pediatrician Heinrich Lehndorff (1908). Note the extreme lumbar lordosis, reflecting a combination of weakness and hip contractures.

Sources:
Zappert J. Die Epidemie der Poliomyelitis acuta epidemica. [Heine-Medinsche. Krankheit] in Wien und Nieder-Oester reich. Jahre 1908.
Oppenheim H. Text-book of nervous disease for physicians and students: authorized translation by Alexander Bruce. 5th edition. Edinburgh: Otto Schultze & Co, 1911;1:209.

See also: Lanska DJ. A human quadrupedal gait following poliomyelitis: From the Dercum-Muybridge collaboration [1885]. Neurology 2016;86:872-6.

Late-stage, carmine preparation from the spinal cord of a 76-year-old man. The cells of the anterior horn, still recognizable microscopically, are brought out by retouching. (Source: Bing R. A textbook of nervous diseases for students and practising physicians in thirty lectures. Authorized translation by Charles L Allen. New York: Rebman Co, 1921.)

Poliomyelitis acuta having run its course. Section of the lumbar cord; staining according to Weigert. Narrowing of the left half of the spinal cord section; atrophy and sclerosis of the anterior horn; degeneration of the anterior roots on the left side. (From Schmaus). (Source: Ibrahim J. Poliomyelitis anterior acuta [acute spinal infantile paralysis]. In: Burr CW, editor. Text-book on nervous diseases. Philadelphia: P Blakiston’s Son & Co, 1915:793-810.)

HQ=headquarters. (Composite image prepared by Dr. Douglas J Lanska from publicly available information on Wikimedia Commons.)

This includes all reported cases of wild polioviruses and vaccine-derived polioviruses. (Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. Published online at OurWorldInData.org 2017, last revised 2022. Retrieved from: https://ourworldindata.org/polio. Creative Commons Attribution 4.0 International License [CC BY 4.0], https://creativecommons.org/licenses/by/4.0.)

Shown is the "base case" reported by Duintjer Tebbens and colleagues. (Sources: Dattani S, Spooner F, Ochmann S, Roser M. Polio. Published online at OurWorldInData.org 2017, last revised 2022. Retrieved from: https://ourworldindata.org/polio. Duintjer Tebbens RJ, Pallansch MA, Cochi SL, et al. Economic analysis of the global polio eradication initiative. Vaccine 2010;29[2]:334-43. Creative Commons Attribution 4.0 International License [CC BY 4.0], https://creativecommons.org/licenses/by/4.0. Reformatted and rearranged from original by Dr. Douglas J Lanska, but data remain unchanged.)

Reported cases of polio underestimate actual cases because people with acute flaccid paralysis may not be detected and tested for poliovirus in time. (Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. Published online at OurWorldInData.org 2017, last revised 2022. Retrieved from: https://ourworldindata.org/polio. Creative Commons Attribution 4.0 International License [CC BY 4.0], https://creativecommons.org/licenses/by/4.0.)

With the Global Polio Eradication Initiative (GPEI), 105 countries received support for surveillance, childhood immunizations, and campaigns to control outbreaks. (Sources: Thompson KM, Kalkowska DA. An updated economic analysis of the global polio eradication initiative. Risk Anal 2021b;41[2]:393-406. Dattani S, Spooner F, Ochmann S, Roser M. Polio. Published online at OurWorldInData.org 2017, last revised 2022. Retrieved from: https://ourworldindata.org/polio. Creative Commons Attribution 4.0 International License [CC BY 4.0], https://creativecommons.org/licenses/by/4.0.)

World Health Organization data as of August 25, 2020. Abbreviations: bOPV, bivalent oral poliovirus vaccine; mOPV, monovalent oral poliovirus vaccine; tOPV, trivalent OPV; WHA, World Health Assembly; WHO, World Health Organization. (Source: Modlin JF, Bandyopadhyay AS, Sutter R. Immunization against poliomyelitis and the challenges to worldwide poliomyelitis eradication. J Infect Dis 2021;224[12 Suppl 2]:S398-404.)

Data as of May 20, 2014. (Source: Moturi EK, Porter KA, Wassilak SG, et al. Progress toward polio eradication--worldwide, 2013-2014. MMWR Morb Mortal Wkly Rep 2014;63[21]:468-72.)

Other countries include Cameroon (n = 5), Equatorial Guinea (n = 5), Ethiopia (n = 1), Iraq (n = 2), Somalia (n = 5), and Syria (n = 1). (Source: Morales M, Tangermann RH, Wassilak SG. Progress toward polio eradication - worldwide, 2015-2016. MMWR Morb Mortal Wkly Rep 2016;65[18]:470-3.)

Data as of May 3, 2019. (Source: Greene SA, Ahmed J, Datta SD, et al. Progress toward polio eradication - worldwide, January 2017-March 2019. MMWR Morb Mortal Wkly Rep 2019;68[20]:458-62.)

Data as of August 3, 2021. Abbreviation: WPV1 = wild poliovirus type 1. (Source: Bigouette JP, Wilkinson AL, Tallis G, Burns CC, Wassilak SGF, Vertefeuille JF. Progress toward polio eradication - worldwide, January 2019-June 2021. MMWR Morb Mortal Wkly Rep 2021;70[34]:1129-35.)

Data as of May 5, 2022. Abbreviation: WPV1 = wild poliovirus type 1. (Source: Rachlin A, Patel JC, Burns CC, et al. Progress toward polio eradication - worldwide, January 2020-April 2022. MMWR Morb Mortal Wkly Rep 2022;71[19]:650-5.)

This includes reported cases of paralytic polio from any wild poliovirus strain (WPV1, WPV2, WPV3). As can be seen, the predominant type of circulating vaccine-derived poliovirus (cVDPV) was type 2 (cVDPV2). (Source: Dattani S, Spooner F, Ochmann S, Roser M. Polio. Published online at OurWorldInData.org 2017, last revised 2022. Retrieved from: https://ourworldindata.org/polio. Creative Commons Attribution 4.0 International License [CC BY 4.0], https://creativecommons.org/licenses/by/4.0.)

Data as of March 24 to 27, 2020. Abbreviations: cVDPV1 = cVDPV type 1; cVDPV2 = cVDPV type 2. (Source: Alleman MM, Jorba J, Greene SA, et al. Update on vaccine-derived poliovirus outbreaks--worldwide, July 2019 to February 2020. MMWR Morb Mortal Wkly Rep 2020;69[16]:489-95.)

Data as of November 9, 2021. Abbreviations: cVDPV = circulating vaccine-derived poliovirus; cVDPV1 = cVDPV type 1; cVDPV2 = cVDPV type 2; cVDPV3 = cVDPV type 3. (Source: Alleman MM, Jorba J, Greene SA, et al. Update on vaccine-derived poliovirus outbreaks--worldwide, July 2019 to February 2020. MMWR Morb Mortal Wkly Rep 2020;69[16]:489-95.)

Courtesy of Ondrej Mach and Ajay Kumar Goel, World Health Organization. Abbreviations: AFP, acute flaccid paralysis; bOPV, bivalent oral poliovirus vaccine; cVDPV, circulating vaccine-derived poliomyelitis; ES, environmental surveillance; WHO, World Health Organization. (Source: Modlin JF, Bandyopadhyay AS, Sutter R. Immunization against poliomyelitis and the challenges to worldwide poliomyelitis eradication. J Infect Dis 2021;224[12 Suppl 2]:S398-404.)

Note that in 2017 the graphs for wild-type type 1 and cVDPV cross over so that cVDPV exceeds the number of wild-type cases. (Figure prepared by Dr. Douglas J Lanska from data from the Centers for Disease Control and Prevention and the World Health Organization.)

(Sources: CDC; Dauer CC. Incidence of poliomyelitis in the United States in 1945. Public Health Rep [1896] 1946;61:915-21. Original image was not quite square; this has been corrected by Dr. Douglas J Lanska.)

(Figure prepared by Dr. Douglas J Lanska. Source for plotted data: U.S. Census Bureau. No. HS-18. Specified reportable diseases--cases per 100,000 population: 1912 to 2001. Statistical abstract of the United States, 2003. Available at: https://www2.census.gov/library/publications/2004/compendia/statab/123ed/hist/hs-18.pdf.)

Abbreviations: ED = emergency department; VDPV2 = type 2 vaccine-derived poliovirus. Wastewater, also referred to as sewage, includes water from household or building use (eg, toilets, showers, and sinks) that can contain human fecal waste and water from non-household sources (eg, rain and industrial use). Note that more than one positive wastewater sample might have been collected on the same day in Rockland County or Orange County. (Source: Link-Gelles R, Lutterloh E, Schnabel Ruppert P, et al. Public health response to a case of paralytic poliomyelitis in an unvaccinated person and detection of poliovirus in wastewater--New York, June to August 2022. MMWR Morb Mortal Wkly Rep 2022;71[33]:1065-8.)

Six-year-old boy on the Children's Ward of the University Hospital, Philadelphia. (Source: Griffith CP. The diseases of infants and children. Vol. 1. Philadelphia, London: WB Saunders Company,1919. Image edited and restored by Dr. Douglas J Lanska.)

View of the left hip, showing necrotic areas in the centers of some spots. (Source: Boivard D Jr. Meningococcal septicaemia with sterile cerebrospinal fluid. In: Thatcher JS, Woolsey G, editors. Medical and surgical report of the Presbyterian Hospital in the City of New York. Vol. 8. New York City and Jamaica, New York: Polydore Barnes Company Printers, 1908;8:355-71.)

View of the left leg. (Source: Boivard D Jr. Meningococcal septicaemia with sterile cerebrospinal fluid. In: Thatcher JS, Woolsey G, editors. Medical and surgical report of the Presbyterian Hospital in the City of New York. Vol. 8. New York City and Jamaica, New York: Polydore Barnes Company Printers, 1908;8:355-71.)

(Source: Koplik H. The diseases of infancy and childhood designed for the use of students and practitioners of medicine. Fourth edition. Philadelphia and New York: Lea & Fibinger, 1918. Image edited and restored by Dr. Douglas J Lanska.)

(Source: Koplik H. The diseases of infancy and childhood designed for the use of students and practitioners of medicine. Fourth edition. Philadelphia and New York: Lea & Fibinger, 1918. Image edited and restored by Dr. Douglas J Lanska.)

(Source: Smith JL. Cerebro-spinal fever. In: Keating JM, editor. Cyclopaedia of the diseases of children: medical and surgical: the articles written especially for the work by American, British, and Canadian authors. Vol. 1. Philadelphia: JB Lippincott Company, 1889:514-54. Image edited and restored by Dr. Douglas J Lanska.)

(Source: Koplik H. The diseases of infancy and childhood designed for the use of students and practitioners of medicine. Fourth edition. Philadelphia and New York: Lea & Fibinger, 1918. Image edited and restored by Dr. Douglas J Lanska.)

Children's Hospital of Philadelphia. (Source: Griffith CP. The diseases of infants and children. Vol. 1. Philadelphia, London: WB Saunders Company, 1919. Image edited and restored by Dr. Douglas J Lanska.)

(Source: Griffith CP. The diseases of infants and children. Vol. 1. Philadelphia, London: WB Saunders Company, 1919. Image edited and restored by Dr. Douglas J Lanska.)

Children's Hospital of Philadelphia. (Source: Griffith CP. The diseases of infants and children. Vol. 1. Philadelphia, London: WB Saunders Company, 1919. Image edited and restored by Dr. Douglas J Lanska.)

Following acquisition, Neisseria meningitidis (Nme) must survive against host defenses and interactions with other members of the microbiome to inhabit the mucus of the nasopharynx. Eventual binding of the epithelial surface results in passage into the submucosa by transcytosis. (Source: Mikucki A, McCluskey NR, Kahler CM. The host-pathogen interactions and epicellular lifestyle of Neisseria meningitidis. Front Cell Infect Microbiol 2022;12:862935. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Binding of N meningitidis to epithelial cells occurs by interaction of bacterial surface structures with their cognate receptors, resulting in inflammation, cellular restructuring, and transcytosis. (Source: Mikucki A, McCluskey NR, Kahler CM. The host-pathogen interactions and epicellular lifestyle of Neisseria meningitidis. Front Cell Infect Microbiol 2022;12:862935. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

In the bloodstream, Neisseria meningitidis (Nme) must resist antibody- and complement-mediated killing, acquire iron, and attach to the capillary endothelial surface to form microcolonies. Once attached, Neisseria meningitidis possesses several mechanisms to resist the actions of phagocytic cells, including neutrophils and macrophages. (Source: Mikucki A, McCluskey NR, Kahler CM. The host-pathogen interactions and epicellular lifestyle of Neisseria meningitidis. Front Cell Infect Microbiol 2022;12:862935. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Binding of endothelial cells occurs by interaction of meningococcal surface structures with their cognate receptors, resulting in cortical plaque formation, transcytosis, and breakdown of tight junctions. (Source: Mikucki A, McCluskey NR, Kahler CM. The host-pathogen interactions and epicellular lifestyle of Neisseria meningitidis. Front Cell Infect Microbiol 2022;12:862935. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Scanning electron micrograph of a single N meningitidis cell (colorized in blue) with its dense meshwork of pili (colorized in yellow). The scale bar is 1 μm. (Courtesy of Arthur Charles-Orszag, adapted by him from: Charles-Orszag A, Tsai FC, Bonazzi D, et al. Adhesion to nanofibers drives cell membrane remodeling through one-dimensional wetting. Nat Commun 2018;9[1]:4450. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Arrowheads show plasma membrane protrusions. Scale bar, 500 nm. (Source: Charles-Orszag A, Tsai FC, Bonazzi D, et al. Adhesion to nanofibers drives cell membrane remodeling through one-dimensional wetting. Nat Commun 2018;9[1]:4450. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Colorized crop shows plasma membrane protrusions (magenta, dotted lined) attached alongside bacterial type IV pili (yellow). Bacterial type IV pili have been stabilized with a monoclonal antibody. Abbreviation: T4P, bacterial type IV pili. Scale bars, 1 μm and 200 nm. (Source: Charles-Orszag A, Tsai FC, Bonazzi D, et al. Adhesion to nanofibers drives cell membrane remodeling through one-dimensional wetting. Nat Commun 2018;9[1]:4450. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Bacterial type IV pili have been labeled with immunogold. Bacterial type IV pili have been stabilized with a monoclonal antibody and labeled with immunogold. Abbreviations: Protr, protrusions; T4P, bacterial type IV pili. Scale bars, 500 nm and 200 nm. (Source: Charles-Orszag A, Tsai FC, Bonazzi D, et al. Adhesion to nanofibers drives cell membrane remodeling through one-dimensional wetting. Nat Commun 2018;9[1]:4450. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Transmission electron micrograph shows plasma membrane protrusions embedded in a meshwork of bacterial type IV pili. Abbreviation: T4P, bacterial type IV pili. Scale bars, 200 nm. (Source: Charles-Orszag A, Tsai FC, Bonazzi D, et al. Adhesion to nanofibers drives cell membrane remodeling through one-dimensional wetting. Nat Commun 2018;9[1]:4450. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Transmission electron micrograph shows plasma membrane protrusions embedded in a meshwork of bacterial type IV pili labeled with immunogold. Abbreviation: T4P, bacterial type IV pili. Scale bars, 200 nm and 50 nm. (Source: Charles-Orszag A, Tsai FC, Bonazzi D, et al. Adhesion to nanofibers drives cell membrane remodeling through one-dimensional wetting. Nat Commun 2018;9[1]:4450. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

N meningitis infects trigeminal Schwann cells, resulting in the formation of multinuclear cells or cells with budding nuclei or horseshoe nuclei. (Source: Delbaz A, Chen M, Jen FE, et al. Neisseria meningitidis induces pathology-associated cellular and molecular changes in trigeminal Schwann cells. Infect Immun 2020;88[4]:e00955-19. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Note how the sulci are obscured by the exudate. (Source: Koplik H. The diseases of infancy and childhood designed for the use of students and practitioners of medicine. Fourth edition. Philadelphia and New York: Lea & Fibinger, 1918. Image edited and restored by Dr. Douglas J Lanska.)

Note how the sulci are obscured by the exudate. (Source: Koplik H. The diseases of infancy and childhood designed for the use of students and practitioners of medicine. Fourth edition. Philadelphia and New York: Lea & Fibinger, 1918. Image edited and restored by Dr. Douglas J Lanska.)

Section of the spinal cord, showing the purulent exudate on the surface, more marked posteriorly and involving the anterior and posterior nerve roots. (Source: Koplik H. The diseases of infancy and childhood designed for the use of students and practitioners of medicine. Fourth edition. Philadelphia and New York: Lea & Fibinger, 1918. Image edited and restored by Dr. Douglas J Lanska.)

(Source: Huang L, Fievez S, Goguillot M, et al. A database study of clinical and economic burden of invasive meningococcal disease in France. PLoS One 2022;17[4]:e0267786. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Rates are graphed for meningococcal infection (red), meningococcal meningitis (green), and meningococcemia (blue). (Source: Walter S, Gil-Prieto R, Gil-Conesa M, Rodriguez-Caravaca G, San Román J, Gil de Miguel A. Hospitalizations related to meningococcal infection in Spain from 1997 to 2018. BMC Infect Dis 2021;21[1]:1215.)

Rates are graphed for ages less than 1 (red), less than 2 (yellow), less than 5 (green), 5 to 9 (blue), and 10 to 14 (purple). Note that the first three age groups overlap. (Source: Walter S, Gil-Prieto R, Gil-Conesa M, Rodriguez-Caravaca G, San Román J, Gil de Miguel A. Hospitalizations related to meningococcal infection in Spain from 1997 to 2018. BMC Infect Dis 2021;21[1]:1215.)

Rates are graphed for ages less than 1 (red), less than 2 (yellow), less than 5 (green), 5 to 9 (blue), and 10 to 14 (purple). Note that the first three age groups overlap. (Source: Walter S, Gil-Prieto R, Gil-Conesa M, Rodriguez-Caravaca G, San Román J, Gil de Miguel A. Hospitalizations related to meningococcal infection in Spain from 1997 to 2018. BMC Infect Dis 2021;21[1]:1215.)

(Figure by Dr. Douglas J Lanska, based on tabular data in: Walter S, Gil-Prieto R, Gil-Conesa M, Rodriguez-Caravaca G, San Román J, Gil de Miguel A. Hospitalizations related to meningococcal infection in Spain from 1997 to 2018. BMC Infect Dis 2021;21[1]:1215.)

(Source: Modification of work by the Centers for Disease Control and Prevention by CNX OpenStax on November 11, 2016. Copyright Holders: OpenStax Microbiology Publishers: OpenStax Microbiology Latest Version: 4.4 First Publication Date: Oct 17, 2016 Latest Revision: Nov 11, 2016. Creative Commons Attribution License [By 4.0], http://creativecommons.org/licenses/by/4.0.)

Bar graph of annual meningitis cases (blue bars) and deaths (blue bars) from meningitis reported from 1928 to 2018 in countries within the African meningitis belt. Note that meningitis case information is unavailable for the period 1948–1957 and that this temporal gap is omitted in the bar graph. The scales for cases and deaths are the left and right vertical axes, respectively. (Source: Mazamay S, Guégan JF, Diallo N, et al. An overview of bacterial meningitis epidemics in Africa from 1928 to 2018 with a focus on epidemics "outside-the-belt." BMC Infect Dis 2021;21[1]:1027. Creative Commons Attribution License [By 4.0], http://creativecommons.org/licenses/by/4.0.)

The areas in grey illustrate the different countries belonging to the meningitis belt. Note that meningitis case information is unavailable for the period 1948–1957. Typographical errors in the figure legend in the original have been corrected by Dr. Douglas J Lanska. (Source: Mazamay S, Guégan JF, Diallo N, et al. An overview of bacterial meningitis epidemics in Africa from 1928 to 2018 with a focus on epidemics "outside-the-belt." BMC Infect Dis 2021;21[1]:1027. Creative Commons Attribution License [By 4.0], http://creativecommons.org/licenses/by/4.0.)

Bar graph of case counts (blue bars) and death counts (blue bars) of meningitis reported from 1928 to 2018 in countries outside of the African meningitis belt. Countries are ranked from left to right according to the number of cases reported. Note that meningitis case information is unavailable for the period 1948–1957. The scales for cases and deaths are the left and right vertical axes, respectively. (Source: Mazamay S, Guégan JF, Diallo N, et al. An overview of bacterial meningitis epidemics in Africa from 1928 to 2018 with a focus on epidemics "outside-the-belt." BMC Infect Dis 2021;21[1]:1027. Creative Commons Attribution License [By 4.0], http://creativecommons.org/licenses/by/4.0.)

Bar graph of confirmed cases of meningitis and the responsible pathogens, Africa, 2000-2010 (before the MenAfrivac targeting N meningitidis serotype A). Abbreviation: Nm, Neisseria meningitidis. (Source: Mazamay S, Guégan JF, Diallo N, et al. An overview of bacterial meningitis epidemics in Africa from 1928 to 2018 with a focus on epidemics "outside-the-belt." BMC Infect Dis 2021;21[1]:1027. Creative Commons Attribution License [By 4.0], http://creativecommons.org/licenses/by/4.0.)

Bar graph of confirmed cases of meningitis and the responsible pathogens, Africa, 2011-2017 (after MenAfrivac targeting N meningitidis serotype A). Abbreviation: Nm, Neisseria meningitidis. (Source: Mazamay S, Guégan JF, Diallo N, et al. An overview of bacterial meningitis epidemics in Africa from 1928 to 2018 with a focus on epidemics "outside-the-belt." BMC Infect Dis 2021;21[1]:1027. Creative Commons Attribution License [By 4.0], http://creativecommons.org/licenses/by/4.0.)

Spatial distribution of meningitis cases by country in Africa, 2000-2010 (before MenAfrivac targeting N meningitidis
serotype A). The areas in grey illustrate the different countries belonging to the meningitis belt. Typographical errors in the figure legend in the original have been corrected by Dr. Douglas J Lanska. (Source: Mazamay S, Guégan JF, Diallo N, et al. An overview of bacterial meningitis epidemics in Africa from 1928 to 2018 with a focus on epidemics "outside-the-belt." BMC Infect Dis 2021;21[1]:1027. Creative Commons Attribution License [By 4.0], http://creativecommons.org/licenses/by/4.0.)

Spatial distribution of meningitis cases by country in Africa, 2011-2017 (after MenAfrivac targeting N meningitidis serotype A). The areas in grey illustrate the different countries belonging to the meningitis belt. Typographical errors in the figure legend in the original have been corrected by Dr. Douglas J Lanska. (Source: Mazamay S, Guégan JF, Diallo N, et al. An overview of bacterial meningitis epidemics in Africa from 1928 to 2018 with a focus on epidemics "outside-the-belt." BMC Infect Dis 2021;21[1]:1027. Creative Commons Attribution License [By 4.0], http://creativecommons.org/licenses/by/4.0.)

Bar graph of case counts (blue bars) and death counts (blue bars) of meningitis reported from 1928 to 2018 in countries within the African meningitis belt. Countries are ranked from left to right according to the number of cases reported. Note that meningitis case information is unavailable for the period 1948-1957. The scales for cases and deaths are the left and right vertical axes, respectively. (Source: Mazamay S, Guégan JF, Diallo N, et al. An overview of bacterial meningitis epidemics in Africa from 1928 to 2018 with a focus on epidemics "outside-the-belt." BMC Infect Dis 2021;21[1]:1027. Creative Commons Attribution License [By 4.0], http://creativecommons.org/licenses/by/4.0.)

The map was created by Nederlandse Leeuw on December 2, 2020. Creative Commons Attribution-Share Alike 4.0 International License, https://creativecommons.org/licenses/by-sa/4.0/deed.en. The composite image is by Dr. Douglas J Lanska.)

Photomicrograph of a Gram stain of spinal fluid at 1000x magnification. Neisseria meningitidis grew from this spinal fluid. Numerous polymorphonuclear leukocytes and the classic Gram-negative diplococci morphology are visible. (Photomicrograph by Microman12345 on February 13, 2019. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Transmission electron microscopic image reveals some of the ultrastructural features exhibited by Bacillus anthracis bacteria. Note that the elongated bacteria were cut in their longitudinal plane, whereas the round-shaped bacteria were sectioned in their transaxial plane. (Image taken by CDC Pathologist Sherif R Zaki (1955-2021) and Elizabeth White in 2001. Courtesy of Centers for Disease Control and Prevention Public Health Image Library. Image 1827.)

Transmission electron microscopic image of Bacillus anthracis bacteria from an anthrax culture, showing cell division (A) and an endospore (B). (Image taken by CDC Pathologist Sherif R Zaki [1955-2021] and Elizabeth White in 2001. Courtesy of Centers for Disease Control and Prevention Public Health Image Library, image 1813.)

This photomicrograph reveals some of the ultrastructural morphology of Bacillus anthracis bacteria, which had been processed using M'Fadyean capsule stain and grown at 35°C on a growth medium of defibrinated horse blood. (Photomicrograph taken in 2002 by Larry Stauffer, Oregon State Public Health Laboratory Courtesy of Centers for Disease Control and Prevention Public Health Image Library. Image 1881.)

Under a magnification of 1000X and using the malachite green spore staining technique, this photomicrograph highlights the green-stained endospores seen amongst these red-colored, Bacillus anthracis bacteria. (Photomicrograph taken in 2002 by Larry Stauffer, Oregon State Public Health Laboratory Courtesy of Centers for Disease Control and Prevention Public Health Image Library. Image 1896.)

Photomicrograph of Gram-stained culture sample, depicts chains of Gram-positive, rod-shaped, Bacillus anthracis bacteria. (Photomicrograph taken in 1980 by Dr. James C Feeley. Courtesy of Centers for Disease Control and Prevention Public Health Image Library, image 2105.)

Gram-stained photomicrograph depicting numerous gram-positive, rod-shaped, Bacillus anthracis bacteria, which are arranged in long filamentous strands. Magnification 1150x. (Photomicrograph taken in 1966 by Dr. Alan Lawrence Brodsky (1941-2016). Courtesy of Centers for Disease Control and Prevention Public Health Image Library, image 20496.)

This image depicts a view of a Petri dish culture plate, which was partitioned down its center to perform an encapsulation test. On the left is a bicarbonate agar growth medium, and on the right is a blood agar growth medium. Each half of the plate was inoculated with the bacterium, Bacillus anthracis. Note the different morphologic characteristics exhibited by the same microorganism, when grown on different growth media. In this case, this proved to result in a positive encapsulation test, with the colonies produced on the bicarbonate medium exhibiting a smooth appearance, whereas those cultivated on the blood agar medium exhibited a rough appearance. (Courtesy of the Centers for Disease Control and Prevention Public Health Image Library, image 2106, 1980. Photograph by Dr. James Feeley, CDC. Public domain.)

Viewed from the side, this low-magnification view of a Petri dish culture plate, shows two Bacillus anthracis bacterial colonies. The colony on the left was untouched, whereas the colony on the right was teased, thereby illustrating its characteristic colonial tenacity: a small spire of colonial matter remained standing on its own support without toppling. (Photomicrograph taken in 1966 by Dr. Alan Lawrence Brodsky (1941-2016). Courtesy of Centers for Disease Control and Prevention Public Health Image Library, image 20500.)

Under very low magnification (5x), this photograph shows a close view of a Petri dish culture plate, upon which colonies of Bacillus anthracis bacteria had been cultivated. This view shows a single colony was featured, which exhibited a classic "medusa-head" or "judge's wig" morphology, a term given to colonies whose edges resemble a tangled mass of curly hair. (Photomicrograph taken in 1966 by Dr. Alan Lawrence Brodsky (1941-2016). Courtesy of Centers for Disease Control and Prevention Public Health Image Library, image 20498.)

Under low-power magnification (10x), this photograph depicts the colonial growth displayed by Sterne strain members of the Gram-positive bacterium, Bacillus anthracis, which were cultured on sheep blood agar for 48 hours at 37°C. (Photograph taken in 2014 by Dr. Todd Parker, Associate Director for Laboratory Science, Division of Preparedness and Emerging Infections at CDC. Courtesy of Centers for Disease Control and Prevention Public Health Image Library, image 17099.)

Under very low magnification (2.5x), this photograph shows a close view of a Petri dish culture plate, upon which colonies of Bacillus anthracis bacteria had been cultivated, each exhibiting a roughly textured surface and irregular edges. (Photomicrograph taken in 1966 by Dr. Alan Lawrence Brodsky [1941-2016]. Courtesy of Centers for Disease Control and Prevention Public Health Image Library, image 20499.)

"Wax no. 66, Hand; Anthrax." Created by Parisian company Maison Tramond as a teaching aid. (Courtesy of the Historical Collections Division, National Museum of Health and Medicine Washington, DC. Creative Commons Attribution 2.0 Generic License [CC BY 2.0], https://creativecommons.org/licenses/by/2.0.)

View of a man's left forearm, showing a large cutaneous lesion, which had been diagnosed as a case of cutaneous anthrax caused by the bacterium, Bacillus anthracis. Note the characteristic dark-brown to black-colored eschar that covered the lesion. The bacterium derives its name from such eschars because the color resembles that of anthracite coal. (Photograph by Georgian Field Epidemiology Training Program resident, Archil Navdarashvili, while at Rustavi Hospital, in the country of Georgia, on August 25, 2012. Courtesy of Centers for Disease Control and Prevention Public Health Image Library, image 1982. Image cropped by Dr. Douglas J Lanska.)

Lateral view of a patient’s right forearm and hand, showing a large cluster of boils, or carbuncles, located primarily on the hand and wrist, which had manifested during a cutaneous anthrax infection caused by the bacterium, Bacillus anthracis. (Courtesy of Centers for Disease Control and Prevention Public Health Image Library, image 20868, 1966. Image provided by Dr. Herman Miranda, University of Trujello, Peru. Image cropped by Dr. Douglas J Lanska.)

Dorsal view of a patient’s right forearm and hand, showing a cluster of boils, or carbuncles, located primarily on the hand and wrist, which had manifested during a cutaneous anthrax infection caused by the bacterium Bacillus anthracis. (Courtesy of Centers for Disease Control and Prevention Public Health Image Library, image 20869, 1966. Photograph by OT Chambers.)

(Source: Chamberland C. Le charbon et la vaccination charbonneuse: d'après les travaux récents de M. Pasteur [Anthrax and anthrax vaccination: according to the recent works of M. Pasteur]. Paris: Bernard Tignol, 1883. Courtesy of the Wellcome Collection, London, England. Image edited by Dr. Douglas J Lanska.)

Lithograph by Christian Schultz (1817-1882) after photograph by French photographer Pierre Petit (1832-1909). (Courtesy of the Bibliothèque interuniversitaire de Santé https://www.biusante.parisdescartes.fr/histoire/images/index.php?refphot=CIPC0022. Licence Ouverte, version 1.0/Open License. Image edited by Dr. Douglas J Lanska.)

(Source: Louis Georges Neumann, professeur à l'École vétérinaire de Toulouse. Courtesy of the Bibliothèque interuniversitaire de Santé. Public domain. Image edited by Dr. Douglas J Lanska.)

(x500) Section from the kidney of a rabbit with anthrax. The glomerulus, partially densely filled with bacilli. (Source: Koch R. Zur Untersuchung von pathogen Organism. Mitheilungen aus dem Kaiserlichen Gesundhetisamte 1881a;1:1-48. Table V. No. 26. Table V. No. 28.)

(x700) Section of liver from rabbit dying of anthrax. All capillaries are more or less filled with anthrax bacilli. Individual anthrax bacilli appear in the capillary network surrounding the liver cells. (Source: Koch R. Zur Untersuchung von pathogen Organism. Mitheilungen aus dem Kaiserlichen Gesundhetisamte 1881a;1:1-48. Table V. No. 26.)

(x700) Anthrax bacilli that had grown into long filaments and formed spores after having been cultured in aqueous humor. The preparation was dried on a coverslip" to bring the threads into one plane for photographing," then rehydrated in potassium acetate (potash) and photographed without staining. (Source: Koch R. Verfahren zur Untersuchung, zum Conservieren und Photographiren der Bakterien. Beiträge zur Biologie der Pflanzen 1877;2:399-434.)

(x700) Bacillus anthracis, from infected spleen. A thin layer of tissue was allowed to dry on a coverslip; then the preparation was stained with aniline brown and immersed in glycerol. The technique causes the red blood cells to lose their color, whereas the bacilli and the nuclei of the white blood corpuscles were colored brown. The blood corpuscles appear in the photograph as pale circles, the nuclei of the white blood corpuscles appear rather dark, and the bacilli, because they are colored mostly brown, are extremely strong and dark. The bacilli are clearly articulated and appear truncated rather than rounded at the end. "This truncated and punctured appearance, as assumed by the dried and stained anthrax bacterium, is so characteristic of it that it may be used in the diagnosis of anthrax with perfect certainty. Indeed, a few months ago, in a man who had two days earlier from anthrax in the form of a diffuse swelling on the left side of the neck, the correct diagnosis could be made by the discovery of some bacilli which had this characteristic mark, which latter was confirmed by successful inoculation of the anthrax substance on animals." (Source: Koch R. Verfahren zur Untersuchung, zum Conservieren und Photographiren der Bakterien. Beiträge zur Biologie der Pflanzen 1877;2:399-434.)

(Source: Wagner E, editor. Gesammelte Abhandlungen von Julius Cohnheim [Collected essays by Julius Cohnheim]. Berlin: August Hirschwald, 1885.)

(Source: Portrait of Ferdinand Julius Cohn, vignetted head and shoulders, autographed Ferdinand Cohn. Bulletin of the Institute of History of Medicine, Johns Hopkins Press, Baltimore, Maryland, 1939;VII: Facing Page 49. Courtesy of the Wellcome Collection, London, England. Creative Commons Attribution 4.0 International License, https://creativecommons.org/licenses/by/4.0/deed.en.)

Anthrax bacilli from a mouse spleen after 24 hours of culture in a drop of aqueous humor; (a) in the filaments elongated round spores have developed at regular intervals like a string of pearls; (b) some threads are in the process of dissolving, the spores are free, single or clustered together. (Source: Koch R. Die Ätiologie der Milzbrand-Krankheit, begründet auf die Entwicklungsgeschichte des Bacillus Anthracis. Beiträge zur Biologie der Pflanzen 1876;2[2]:283. Image edited to remove unrelated images and to improve sharpness and contrast by Dr. Douglas J Lanska.)

This represents work Koch did to understand cholera in South Africa, but it undoubtedly portrays a laboratory very close to what he earlier created for his studies of Bacillus anthracis. Photogravure of gouache painting. (Source: Osler W. The evolution of modern medicine: a series of lectures delivered at Yale University on the Silliman Foundation in April 1913. New Haven, Connecticut: Yale University Press, 1922:210. Courtesy of the Wellcome Collection, London, England. Photo number: M0000732. Note: Image has been flipped horizontally by Dr. Douglas J Lanska to match the original image. The Wellcome Collection image is a mirror image of the original. Creative Commons Attribution 4.0 International License, https://creativecommons.org/licenses/by/4.0/deed.en.)

Halftone photomechanical print by German photographer Josef Albert (1825-1886). (Source: Bibliothèque interuniversitaire de Santé. https://www.biusante.parisdescartes.fr/histoire/images/index.php?refphot=CIPB0672. Licence Ouverte, version 1.0/Open License.)

(magnification 1200) (Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920.)

(magnification x500) (Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920.)

(Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920.)

(Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920.)

(Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920.)

Before infection (left) and during the "most acute stage of infection" (right). Note the black eschar and the marked edema of the neck extending to the face and chest. Treatment was limited to washing the wound and applying tincture of iodine. Internal administration of iodine, tonics, and stimulants (quinine, alcohol, coffee), inhalation of oxygen, and experimental serotherapy were also advocated. (Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920. Plates 1 and 2. Edited by Dr. Douglas Lanska.)

In wool manufacturing centers occupational anthrax was commonly known as “woolsorters’ disease." (Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920. Plate 9.)

(Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920. Plate 3.)

(Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920. Plate 5.)

After skinning and before stretching and drying, all excess flesh must be removed from the pelt. This process is called “fleshing.” If all the fat is not removed, grease burns will occur. In addition, fatty pelts do not dry properly and will spoil quickly. (Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920. Plate 11.)

Workers are shown scraping hides taken from lime vats in which they have been submerged until the hair is loosened. (Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920. Plate 10.)

Hides and skins were usually imported in a raw state and had to be tanned before they could be used in manufacture. At the tannery, the skins were sorted and then soaked, which brought the “dry” hides to a moist flexible state that allowed more complete absorption of the tannin from the subsequent tan liquors. The “soak” removed much of the earth, blood, dirt, and spores adhering to the hides, which considerably decreased the risk of anthrax infection, although it did not destroy the spores. (Source: Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920. Plate 8.)

(Source:Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920. Plate 4.)

(Source:Andrews JB. Anthrax as an occupational disease. Bulletin of the United States Bureau of Labor Statistics No. 205. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1917. Andrews JB. Anthrax as an occupational disease. Revision of Bulletin 205. Bulletin of the United States Bureau of Labor Statistics No. 267. Industrial accidents and hygiene series. Washington, DC: U.S. Government Printing Office, 1920. Plate 6.)

One monomer is gray, and one is color coded by domain (blue, b-roll; yellow, wing; red, b-ladder; and salmon, spaghetti loop). The disordered flexible loop is indicated by orange dashed lines. (Source: Wessel AW, Doyle MP, Engdahl TB, Rodriguez J, Crowe JE Jr, Diamond MS. Human monoclonal antibodies against NS1 protein protect against lethal West Nile virus infection. mBio 2021;12[5]:e0244021. Creative Commons Attribution 4.0 International License, https://creativecommons.org/licenses/by/4.0.)

One monomer is gray, and one is color coded by domain (blue, b-roll; yellow, wing; red, b-ladder; and salmon, spaghetti loop). The disordered flexible loop is indicated by orange dashed lines. (Source: Wessel AW, Doyle MP, Engdahl TB, Rodriguez J, Crowe JE Jr, Diamond MS. Human monoclonal antibodies against NS1 protein protect against lethal West Nile virus infection. mBio 2021;12[5]:e0244021. Creative Commons Attribution 4.0 International License, https://creativecommons.org/licenses/by/4.0.)

(Source: Mencattelli G, Ndione MH, Rosà R, et al. Epidemiology of West Nile virus in Africa: an underestimated threat. PLoS Negl Trop Dis 2022;16[1]:e0010075. Creative Commons Attribution 4.0 International License [CC-BY 4.0], https://creativecommons.org/licenses/by/4.0.)

(Source: Mencattelli G, Ndione MH, Rosà R, et al. Epidemiology of West Nile virus in Africa: an underestimated threat. PLoS Negl Trop Dis 2022;16[1]:e0010075. Creative Commons Attribution 4.0 International License [CC-BY 4.0], https://creativecommons.org/licenses/by/4.0.)

Locations in Germany with detected West Nile virus overwintering (red dot) and of collection sites without virus detection (uncolored dots). (Source: Kampen H, Tews BA, Werner D. First evidence of West Nile virus overwintering in mosquitoes in Germany. Viruses 2021;13[12]:2463. Creative Commons Attribution [CC BY] license, https:// creativecommons.org/licenses/by/4.0.)

Brain MRI performed at 16 days from symptoms onset, showing lobar white matter hyperintensities (black arrows) on T2-FLAIR sequences. Motion artifacts are present. (Source: Falcinella C, Allegrini M, Gazzola L, et al. Three case reports of West Nile virus neuroinvasive disease: lessons from real-life clinical practice. BMC Infect Dis 2021;21(1):1132. Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0.)

Three-dimensional computer-generated image of Neisseria diplococcal bacteria. Extending from the organisms’ exterior are type IV pili, or hair-like appendages, which improve surface adherence. The artistic recreation was based on scanning electron microscopic imagery. Image by Alissa Eckert, Medical Illustrator, for the Antibiotic Resistance Coordination and Strategy Unit, Centers for Disease Control and Prevention, 2013. (Courtesy of the Public Health Image Library, Centers for Disease Control and Prevention.)

Neisseria meningitidis uses adhesive organelles called Type IV pili, which help them interact with each other to form colonies and adhere to the surface of epithelial cells in the human nasal tract. Pili can be several microns in length but are only 7 nm in diameter. In this image, the bacteria have been stained with salts of uranium to increase contrast in the electron microscope. Individual pili can be seen radiating from the bacterium, in addition to outer membrane vesicles that have been shed by the bacteria. Electron microscopic image by Eric Johnson. (Courtesy of the Wellcome Collection, London. Attribution 4.0 International [CC BY 4.0].)

Three-dimensional, computer-generated image, of diplococcal, gram-negative, Neisseria meningitidis bacteria, based on scanning electron microscopic (SEM) imagery. (Image by Sarah Bailey Cutchin, Centers for Disease Control and Prevention, 2016. Courtesy of the Public Health Image Library, Centers for Disease Control and Prevention.)

This 20-month-old infant underwent amputations including both feet and her left hand at the wrist, after having contracted meningococcal septicemia, or meningococcemia. The disease caused multiple arterial occlusions, which resulted in gangrene in the amputated extremities. (Contributed by Dr. Douglas Lanska.)

A 4-month-old female infant’s gangrenous left knee due to meningococcemia. This infection causes arterial occlusions, which in turn cause ischemic insults to develop with ensuing gangrene of the affected body regions. (Courtesy of the Public Health Image Library, Centers for Disease Control and Prevention.)

A 4-month-old female infant’s gangrenous feet, due to meningococcemia. This infection causes arterial occlusions, which in turn cause ischemic insults to develop with ensuing gangrene of the affected body regions. (Courtesy of the Public Health Image Library, Centers for Disease Control and Prevention.)

A 4-month-old female infant’s gangrenous right hand, due to meningococcemia. This infection causes arterial occlusions, which in turn, cause ischemic insults to develop with ensuing gangrene of the affected body regions. (Courtesy of the Public Health Image Library, Centers for Disease Control and Prevention.)

A man's chest, revealing a red lesion on the skin in the right lateral pectoral region. The lesion was determined to be due to meningococcemia. (Courtesy of the Public Health Image Library, Centers for Disease Control and Prevention.)

(Photograph by Elias Goldensky, Philadelphia. Source: The World's Work: A History of Our Time. New York: Doubleday, Page & Company, 1904;9[2]:5550.)

German caricature showing von Behring extracting horse serum with a tap. Even in caricature, the recognition went to Behring and not Ehrlich. (Courtesy of the Wellcome Collection, London. Public domain.)

(Courtesy of the Wellcome Collection, London. Attribution 4.0 International [CC BY 4.0].)

Ehrlich was instrumental in the work that developed serum therapy for diphtheria. Although Behring cheated him out of both financial reward and recognition, Ehrlich did win the 1908 Nobel Prize in Physiology or Medicine for his contributions to immunology. (Courtesy of the U.S. Library of Congress.)

Behring introduced serum therapy for diphtheria and was controversially awarded a solo Nobel Prize in Physiology or Medicine for this in 1901. Actually, the work had been done by both Behring and Paul Ehrlich (1854-1915), but Behring apparently cheated Ehrlich out of both recognition and financial reward. They had produced their diphtheria serum by repeatedly injecting the bacterial toxin into a horse. The serum was then used effectively during an epidemic in Germany. A chemical company offered a contract to both men, but Behring took the considerable financial rewards for himself. (Courtesy of the University of Marburg, Germany.)

Wiechselbaum identified the meningococcus (designated as Diplococcus intracellularis meningitidis) in cerebrospinal fluid and established the connection between the organism and epidemic meningitis. (Courtesy of the U.S. National Library of Medicine.)

With Ettore Marchiafava (1847-1935), Celi described intracellular micrococci in cerebrospinal fluid. (Courtesy of Wikimedia Commons. Public domain. Photograph restored by Dr. Douglas J Lanska.)

With Angelo Celli (1886-1914), Marchiafava described intracellular micrococci in cerebrospinal fluid. (Courtesy of the Wellcome Collection, London. Public domain. Photograph restored by Dr. Douglas J Lanska.)

Neisser discovered Neisseria gonorrhoeae in 1879. (Photograph courtesy of the U.S. National Library of Medicine. Photograph restored by Dr. Douglas J Lanska.)

Incidence peaks in the late summer and early autumn. A total of 21,869 cases were reported in the United States from 2009 to 2018. (Source: McDonald E, Mathis S, Martin SW, Staples JE, Fischer M, Lindsey NP. Surveillance for West Nile Virus Disease - United States, 2009-2018. MMWR Surveill Summ 2021;70(1):1-15.)

A total of 12,835 neuroinvasive cases were reported in the United States from 2009 to 2018. Incidence is expressed as cases per 100,000 population. Incidence calculated using U.S. Census Bureau population estimates for July 1 of each year of the reporting period. (Source: McDonald E, Mathis S, Martin SW, Staples JE, Fischer M, Lindsey NP. Surveillance for West Nile Virus Disease - United States, 2009-2018. MMWR Surveill Summ 2021;70(1):1-15.)

A total of 91 cases of wild poliovirus type 1 (WPV1) and 71 cases of vaccine-derived poliovirus type 2 (VDPV2) were reported from January 2016 to July 2020, with a marked exacerbation in 2020 (data as of August 29, 2020). Abbreviations: aVDPV2 = ambiguous vaccine-derived poliovirus type 2; cVDPV2 = circulating vaccine-derived poliovirus type 2; WPV1 = wild poliovirus type 1. aVDPVs are isolates with no evidence of person-to person transmission or from persons with no known immunodeficiency; cVDPVs are isolates for which there is evidence of person-to-person transmission in the community. (Source: U.S. Centers for Disease Control and Prevention. Martinez M, Akbar IE, Wadood MZ, Shukla H, Jorba J, Ehrhardt D. Progress toward poliomyelitis eradication - Afghanistan, January 2019-July 2020. MMWR Morb Mortal Wkly Rep 2020;69(40):1464-8.)

During 2019, 147 WPV1 cases were reported in Pakistan, more than 12 times the 12 reported cases during 2018. Since the detection of the first cVDPV2 case in July 2019 through September 15, 2020, 81 cases were reported. Abbreviations: cVDPV2 = circulating vaccine-derived poliovirus type 2; WPV1 = wild poliovirus type 1. cVDPVs are isolates for which there is evidence of person-to-person transmission in the community. (Source: U.S. Centers for Disease Control and Prevention. Hsu CH, Rehman MS, Bullard K, Jorba J, et al. Progress toward poliomyelitis eradication - Pakistan, January 2019-September 2020. MMWR Morb Mortal Wkly Rep 2020;69(46):1748-52.)

(A) A frontal view of the microcephaly. (B) Normal tone and alertness. (C) CT scan shows calcifications and ventriculomegaly. (D) MRI shows polymicrogyria. (E) Diffuse calcifications on MRI. (F) Small cerebellum and redundant occipital skin on MRI. (Contributed by Dr. Abelardo Araujo.)

Neurocysticercosis in a 26-year-old man originally from Congo. (A) T2 FLAIR and (B) contrast T1-weighted images reveal a cystic lesion in the right temporal lobe with no perilesional edema or contrast enhancement. (Contributed by Dr. Lama Abdel Wahed.)

(A) T2 FLAIR imaging reveals multiple space-occupying lesions in the cortex and the basal ganglia with surrounding massive vasogenic edema with midline shift, hydrocephalus, and impending herniation. (B) T1-weighted postgadolinium image reveals ring enhancement with the classic “eccentric target” sign. (Contributed by Dr. Lama Abdel Wahed.)

Progressive multifocal leukoencephalopathy in a 67-year-old woman with idiopathic immune complex-mediated membranoproliferative glomerulonephritis with stage III chronic kidney disease. Brain biopsy was performed prior to this MRI. (A) T2 FLAIR sequence reveals white matter lesions that spare the cortex with associated enhancement on the T1-weighted post-gadolinium image. (Contributed by Dr. Lama Abdel Wahed.)

MRI in patient with Creutzfeldt-Jacob disease demonstrates cortical ribboning in the bilateral hemispheres, as well as diffusion restriction of the head of the caudate and putamen on (A) diffusion-weighted imaging with present ADC, correlate (B) more prominently on the left. (Contributed by Dr. Lama Abdel Wahed.)

MRI demonstrate abnormal T2 FLAIR hyperintensity in the midbrain and pons, encompassing the left superior colliculus (A) with no associated enhancement (B). (Contributed by Dr. Lama Abdel Wahed.)

(A) T2 FLAIR bithalamic hyperintensities with associated ring-link enhancement on (B) T1-weighted post-gadolinium image. (Contributed by Dr. Lama Abdel Wahed.)

(A) T2 FLAIR hyperintense lesion in the right caudate nucleus with (B) associated punctate enhancement on contrast T1-weighted image. (C and D) images demonstrate similar FLAIR lesions with associated enhancement in the midbrain. (Contributed by Dr. Lama Abdel Wahed.)

These mass lesions are hyperintense on T2-weighted image (A) and hypointense on T1-weighted image (B) with associated ring enhancement post-gadolinium injection. Note that due to its high purulence, there is prominent diffusion restriction on diffusion-weighted image (C) with ADC correlate (D). (Contributed by Dr. Lama Abdel Wahed.)

T2 FLAIR imaging (A) with associated focal pachymeningeal and leptomeningeal enhancement on contrast T1-weighted imaging (B). In the early stages, it was mistaken for a subacute infarct. (Contributed by Dr. Lama Abdel Wahed.)

(A) T2 FLAIR changes in the left insula with associate diffusion restriction (B). (C) T2 FLAIR and (D) diffusion-weighted imaging changes in the left temporal lobe. (Contributed by Dr. Lama Abdel Wahed.)

Map of the range of the Australian paralysis tick (Ixodes holocyclus). (Courtesy of Wikimedia Commons. Creative Commons Attribution 3.0 Unported [CC BY 3.0] license, creativecommons.org/licenses/by/3.0.)

Detailed distribution map of the Australian paralysis tick (Ixodes holocyclus). Image by FHS Roberts (1970). (Courtesy of Wikimedia Commons. With permission.)

Comparison of the stages of engorgement of the Ixodes holocyclus tick (Australian paralysis tick). Although these pictures are not to the same scale, the scutum can be used to compare the relative sizes because the size of the “shield” (scutum) does not change as the female tick engorges. Photographs by Commonsource (2010). (Courtesy of Wikimedia Commons. Creative Commons Attribution 3.0 Unported [CC BY 3.0] license, creativecommons.org/licenses/by/3.0.)

An engorged female Haemophysalis longicornis tick (also called the Bush tick in Australia). This is not the Australian paralysis tick (Ixodes holocyclus), but is shown for comparison with Ixodes holocyclus. Unlike Ixodes holocyclus, all pairs of legs of Haemaphysalis longicornis are of the same shade, the legs are finer, the mouthparts are much shorter, and the shield is rounded. Photographs by Commonsource (2002). (Courtesy of Wikimedia Commons. Creative Commons Attribution 3.0 Unported [CC BY 3.0] license, creativecommons.org/licenses/by/3.0.)

Ixodes holocyclus ticks before and after feeding (shown on the palm of a human hand). These ticks were picked off of koalas in the Koala Hospital in Port Macquarie, New South Wales, Australia. The small tick had not yet started feeding, whereas the other had probably been at work for a couple of days. The amount of blood inside the larger tick is approximately 5 milliliters. Photograph by Bjørn Christian Tørrissen (January 14, 2009). (Courtesy of Wikimedia Commons. Creative Commons Attribution 3.0 Unported [CC BY 3.0] license, creativecommons.org/licenses/by/3.0.)

A moderately engorged Ixodes holocyclus tick attached to a severely paralyzed dog. Photograph by Commonsource (1998). (Courtesy of Wikimedia Commons. Creative Commons Attribution 3.0 Unported [CC BY 3.0] license, creativecommons.org/licenses/by/3.0.)

A fully engorged adult female Ixodes holocyclus tick showing the darker first and fourth pairs of legs. Photograph by Commonsource (2002). (Courtesy of Wikimedia Commons. Creative Commons Attribution 3.0 Unported [CC BY 3.0] license, creativecommons.org/licenses/by/3.0.)

(Courtesy of the U.S. Centers for Disease Control and Prevention. Public domain.)

A female Ixodes holocyclus tick (the so-called Australian paralysis tick) at an early stage of attachment on human skin. Photograph by Kevin Broady. (Courtesy of Wikimedia Commons. Creative Commons Attribution 3.0 Unported [CC BY 3.0] license, creativecommons.org/licenses/by/3.0.)

A female Ixodes holocyclus tick (the so-called Australian paralysis tick) photographed against lined paper for an indication of size. The tick was removed from the coat of a dog that had been in the bush. Photography by AY Arktos (November, 2005) at Batemans Bay, New South Wales, Australia. (Courtesy of Wikimedia Commons. Creative Commons Attribution 2.5 Generic [CC BY 2.5] license, creativecommons.org/licenses/by/2.5.)

A male American dog tick, Dermacentor variabilis, on a human finger (dorsal view). Photograph by Jerry Kirkhart, Los Osos, California (2009). (Courtesy of Wikimedia Commons. Creative Commons Attribution 2.0 International [CC BY 2.0] license, creativecommons.org/licenses/by/2.0.)

Note that larvae have six legs, whereas nymphs and adults have eight legs. (Courtesy of the Public Health Image Library, Centers for Disease Control and Prevention. Public domain.)

(Courtesy of the U.S. Centers for Disease Control and Prevention. Public domain.)

Examples of an early-stage rash in a Rocky Mountain spotted fever patient. (Used with permission from: Centers for Disease Control and Prevention. Available at: www.cdc.gov/rmsf/symptoms/index.html.

Aerobic gram-negative Neisseria meningitidis diplococcal bacteria (aerobic gram-negative, magnification 1150x). (Courtesy of Public Health Image Library, Centers for Disease Control and Prevention; contributed by Dr. Douglas Lanska.)

A photomicrograph of Neisseria meningitidis recovered from the urethra of an asymptomatic male; Magnified 1125X. (Courtesy of Public Health Image Library, Centers for Disease Control and Prevention; contributed by Dr. Douglas Lanska.)

Bacillus anthracis produces the three subunits of anthrax toxin: protective antigen (PA), lethal factor (LF) and edema factor (EF). The 83 kDa form of PA (PA83) binds to either of two type I transmembrane proteins (CMG2 or TEM8) at the cell surface, where it is cleaved by furin-like proteases, leading to the shorter receptor-associated form of PA (PA63) and a soluble fragment (PA20). Upon toxin binding, the receptors are phosphorylated by Src‐like kinases (Src or Fyn), and are ubiquitinated (by Cbl for TEM8, or by an unknown E3 ligase for CMG2). After oligomerization in lipid rafts (dark grey), the receptor-toxin complex is internalized by endocytosis, a process involving clathrin, dynamin, activator protein 1 (AP‐1), actin, and low-density lipoprotein receptor-related protein 6 (LRP6). (Source: Friebe S, van der Goot FG, Bürgi J. The ins and outs of anthrax toxin. Toxins (Basel) 2016;8(3). Creative Commons by Attribution (CC-BY) License.)

Girl with tick attached behind ear and otherwise obscured by hair. Note the swollen lymph node on neck below. Photograph by Bernard Hudson. (Courtesy of Wikimedia Commons. Creative Commons Attribution 3.0 Unported [CC BY 3.0] license, creativecommons.org/licenses/by/3.0.)

By compressing the mouthparts (and not the body of the tick) one avoids squeezing more allergens, toxins, and infectious micro-organisms into the host. Illustration by Commonsource (2005). (Courtesy of Wikimedia Commons. Creative Commons Attribution 3.0 Unported [CC BY 3.0] license, creativecommons.org/licenses/by/3.0.)

The life cycle of a 3-host tick may take 1 to 2 years, depending on whether the tick can find a suitable host between life stages. (1) Female tick lays eggs on ground. (2) The 6-legged larva feeds on small mammals and then drops off to the ground and molts. (3) The 8-legged nymph feeds on a small mammal and then drops off to the ground and molts. (4) Eight-legged adult ticks feed and mate on a larger mammal (including livestock and pets) and then drop off to the ground, where females begin to develop eggs. Illustration by Scott Charlesworth, Purdue University, Medical Entomology Extension. (Source: Department of Entomology, University of Wisconsin-Madison. Courtesy of Wikimedia Commons. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)

Gadolinium-enhanced MRI of a 57-year-old male patient. There is a large, loculated abscess posterior to the cord with severe spinal cord compression. The abscess extends from C7 to T12. (Contributed by Dr. John Greenlee.)

CT and gadolinium-enhanced MRI studies of a patient with recurrent bacterial meningitis. (A) High-resolution CT scan of the temporal bone showing a bony defect in the segment tympani (arrow). (B) and (C) Gadolinium-enhanced MRI scans showing meningitis localized to the area above the defect. (Courtesy of Dr. H. Christian Davidson.)

Distribution of major rabies virus variants among mesocarnivores in the United States, including Puerto Rico, from 2017 through 2021. Darker shading indicates counties with confirmed animal rabies cases in the past 5 years; lighter shading represents counties bordering enzootic counties without animal rabies cases that did not satisfy criteria for adequate surveillance. Small nonenzootic areas with no rabies cases reported in the past 15 years are shaded if they are in the vicinity of known enzootic counties and do not satisfy criteria for adequate surveillance. Rabies virus variants: ARC FX = Arctic fox, AZ FX = Arizona fox, CA SK = California skunk, E RC = Eastern raccoon, MG = Dog-Mongoose, NC SK = North central skunk, and SC SK = South central skunk. (From the Centers for Disease Control and Prevention. Ma X, Bonaparte S, Corbett P, et al. Rabies surveillance in the United States during 2021. J Am Vet Med Assoc 2023.)

Polish-American virologist Albert Sabin (1906-1993) developed the first effective trivalent live-attenuated (oral) poliovirus vaccine. (Contributed by Dr. Douglas Lanska. Source: Woodward T. The Armed Forces Epidemiological Board: its first fifty years. Falls Church, VA: Office of the Surgeon General, Department of the Army, 1990. Public domain photograph of a U.S. Army soldier taken in the course of the person’s official duties.)

O’Connor was Chairman of the National Foundation for Infantile Paralysis that funded the development and testing of polio vaccines, including the Salk killed virus vaccine. He was also later Chairman and President of the American Red Cross (1944-1949) and the League of Red Cross Societies (1945-1950). (Contributed by Dr. Douglas Lanska. Source: Red Cross and Red Crescent Movement History. http://www.redcross.int/en/history/not_oconnor.asp [Accessed 4-23-2017]. Used with permission.)

A 4-month-old female infant with gangrene of the hands and lower extremities due to meningococcemia. (Courtesy of the Public Health Image Library, Centers for Disease Control and Prevention; contributed by Dr. Douglas Lanska.)

A 4-month-old female infant with gangrene of the hands due to meningococcemia. (Courtesy of the Public Health Image Library, Centers for Disease Control and Prevention; contributed by Dr. Douglas Lanska.)

Blood smear showing the presence of a multinucleate lymphocyte, a "flower cell,” typical of HTLV-1 infection. It is pathognomonic of the carrier state, patients with adult T-cell leukemia lymphoma, and HAM/TSP.

Proton density axial MRIs of the head show 2 areas of increased signal (arrows) in the cerebral white matter of a 45-year-old patient with a spastic, wide-based gait, urinary symptoms, and CSF positive for HTLV-1. (Used with permission from: Howard A, Li D, Oger J. MRI contributes to the differentiation between multiple sclerosis and HTLV-1 associated myelopathy in British Columbian coastal natives. Can J Neurol Sci 2003;30:41-8.)

T2-weighted sagittal MRI of the cervical cord demonstrates atrophy in a 32-year-old patient with urinary retention, spastic paraparesis, and HTLV-1 detectable in the CSF. This finding has been described previously in HAM/TSP. Atrophy was found at a similar rate in the patient with multiple sclerosis the authors studied. (Used with permission from: Howard A, Li D, Oger J. MRI contributes to the differentiation between multiple sclerosis and HTLV-1 associated myelopathy in British Columbian coastal natives. Can J Neurol Sci 2003;30:41-8.)

West Nile virus neuroinvasive disease average annual incidence by state in the United States, 1999 to 2020. (From: Centers for Disease Control and Prevention.)

Human LaCrosse virus neuroinvasive disease cases reported by state, 2011 to 2020. (From: Centers for Disease Control and Prevention.)

Powassan virus neuroinvasive disease cases by state}{label:Human cases of Powassan virus neuroinvasive disease cases from 2011 to 2020. (From: Centers for Disease Control and Prevention.)

Human cases of St. Louis encephalitis virus neuroinvasive disease reported by state, 2011 to 2020. (From: Centers for Disease Control and Prevention)

Eastern equine encephalitis virus human disease cases reported by state, 2003 to 2022. (From: Centers for Disease Control and Prevention.)

The natural inapparent cycle is between small birds and Culiseta melanura, a swamp marsh mosquito that does not bite large birds or mammals. Overflow of the cycle into various species of Aedes mosquitoes can amplify the virus into other wild birds and mammals. Aedes species may bite humans, horses, and pheasants, which can develop clinical encephalitis. (Used with permission: Johnson RT. Viral infections of the nervous system. 2nd ed. Philadelphia: Lippincott-Raven, 1998:87-132.)

The mosquito Aedes triseriatus is the vector for La Crosse virus. (Contributed by Dr. Alan Jackson.)