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Epidemics, pandemics and outbreaks · mortality, impairment and response

A global history of epidemics, pandemics and severe outbreaks, from the epidemic at Athens in 430 BCE to the documented end of a renewed mpox international emergency in September 2025. The survey brings together 58 outbreak and continuing-disease groups, with dated recognition, investigations, prevention milestones, accountability and evidence updates. It is a substantial selection rather than every outbreak ever recorded.

Human harm, immediate and lasting

Mass mortality is central, but deaths alone do not capture polio paralysis, congenital rubella and Zika injury, post-encephalitic disability, chronic chikungunya pain, prion disease or post-COVID impairment. Some smaller high-consequence outbreaks are included because they reveal a new agent, expose a dangerous transmission setting or cause profound harm among those affected. The timeline does not imply that every selected outbreak has the same casualty scale.

Ancient Mediterranean epidemics, Japanese smallpox, plague pandemics, colonial American catastrophes, cholera, influenza, African trypanosomiasis and leishmaniasis, HIV, meningitis, SARS, MERS, Ebola, measles, dengue and other infections are compared with their distinct geography and evidence. Tuberculosis and malaria appear through explicitly dated response milestones: 1993 and 1998 are not claims about their origins.

How a hazard becomes a disaster

Entries ask what the agent or hazard was, how exposure occurred, which people were harmed, what amplified transmission, how institutions responded and what persisted afterward. Safe water, vaccination, infection prevention, reliable medical production, food tracing, care and social support address different parts of that chain. War, colonial rule, displacement, poverty and unequal access can worsen harm without replacing microbiological explanation.

Poisoning outbreaks such as Minamata and Spain’s toxic oil syndrome have their own category. Irish potato blight and African rinderpest are included as indirect crop- and livestock-disease catastrophes: people did not acquire those plant or animal diseases as contagious human infections. Their human effects arise through food, livelihoods and associated illness.

What the evidence supports

Sources emphasize WHO, CDC, national public-health agencies, original outbreak investigations, historical testimony and pathogen-genome studies, with scholarly interpretation where needed. Ancient disease names are not automatic modern diagnoses. Athens and Cyprian remain unidentified; smallpox attribution in the Antonine epidemic is qualified. Salmonella in sampled cocoliztli victims is not proof of one cause for every death across Mexico. The cause of encephalitis lethargica remains unresolved.

Numbers preserve their scope. Reported cases, estimated infections, confirmed deaths, survey estimates, modeled deaths and excess mortality are different measures. The DRC Ebola account identifies the later WHO data update used; West African Ebola figures retain their stated surveillance source and period. Historical global death totals are not presented as complete modern censuses.

Navigation, dates and relationships

Use outbreak, region, type and role tags to separate cases and compare responses. Explanatory cards address uncertainty, causal mechanisms, measurement and disability. Relationship notes state whether a connection means a response, a later discovery or an analytical comparison. A line between two outbreaks is not automatically a transmission chain or proof that one caused the other.

All coordinates display in Gregorian CE/BCE. Coarse dates use representative year or month anchors; the first day is for positioning only. Later publication dates are distinguished from the historical events they reinterpret. Approximate date anchors can have dashed outlines; this does not label the documented epidemic itself imaginary or doubtful.

There are six definite duration bands, all for WHO international emergency designations: H1N1, West African Ebola, Zika, COVID-19 and the two separate mpox emergencies. Ending a designation does not mean transmission has ended. Continuing epidemics have moments, with no duration artificially ending on the day this timeline was created. Smallpox and rinderpest eradication are identified separately as stronger endpoints.

Illustrations

The cover is a contemporary photograph of the emergency influenza hospital at Camp Funston, Kansas, in 1918. Twelve freely licensed Commons illustrations include an original cholera map, microscopy, respiratory equipment, vector photography, a treatment unit and later memorials. Each illustrated entry explains what the image shows, gives attribution and identifies its public-domain or Creative Commons status. Microscopy and later memorials are not passed off as photographs of ancient outbreaks.

Otis Historical Archives, National Museum of Health and Medicine · Emergency hospital during Influenza epidemic, Camp Funston, Kansas - NCP 1603.jpg · Public domain. File and attribution. No changes beyond thumbnail rendering/scaling.

Selected source records

82 moments · 0430-01-01T00:00:00Z BCE – 2025-09-05T00:00:00Z CE · by @athan · @athan

A cluster of opportunistic pneumonia marks public recognition of AIDS

  • outbreak: hiv
  • region: united states / global epidemic
  • type: continuing global epidemic
  • role: outbreak / recognition

CDC reports Pneumocystis pneumonia in five previously healthy men in Los Angeles on 5 June 1981. This is an early public recognition of the syndrome later called AIDS, not the origin of HIV: infection had been circulating for decades before the report. Subsequent work identifies HIV and clarifies transmission through sexual exposure, blood and perinatal routes. Without effective treatment, progressive immune damage leaves people vulnerable to opportunistic infections and cancers. Stigma, discrimination and unequal access to care compound the biological harm. Community organization, safer blood systems, prevention and treatment transform the response, while access remains uneven. The early US case description must not be mistaken for the epidemic’s full geography or the identities of all people who can be infected. **Outbreak / comparison:** A cluster of opportunistic pneumonia marks public recognition of AIDS. **Agent or hazard:** Human immunodeficiency viruses. **Evidence and measurement:** 1981 is recognition, not origin; early case series is not the total epidemic burden. **Date:** 1981-06-05 CE; day. Gregorian CE/BCE display, UTC. Year-only and month-only coordinates use the first day for positioning only; they do not assert an exact January 1 or first-of-month event. Ancient dates are proleptic Gregorian year anchors. Pre-reform historical dates retain coarse precision unless explicitly converted. **Sources:** - [CDC MMWR, Pneumocystis pneumonia, Los Angeles, 5 June 1981](https://www.cdc.gov/mmwr/preview/mmwrhtml/june_5.htm) - [US government HIV.gov, A timeline of HIV and AIDS](https://www.hiv.gov/hiv-basics/overview/history/hiv-and-aids-timeline) **Image context:** NIAID scanning electron micrograph of an HIV-infected T cell. Illustrates cellular infection, not a photograph of a specific patient in the 1981 case report. **Credit:** NIAID · HIV-infected T cell (6813384933).jpg · CC BY 2.0. [File and attribution](https://commons.wikimedia.org/wiki/File:HIV-infected_T_cell_(6813384933).jpg). [License](https://creativecommons.org/licenses/by/2.0). No changes beyond thumbnail rendering/scaling. **Connection to Combination antiretroviral therapy changes the course of HIV disease:** Same disease-history comparison: treatment transformation. This link may identify a later response, discovery or separate outbreak. It does not assert uninterrupted transmission from the parent event.

Date precision
day
Coordinate convention
Gregorian CE/BCE display, UTC. Year-only and month-only coordinates use the first day for positioning only; they do not assert an exact January 1 or first-of-month event. Ancient dates are proleptic Gregorian year anchors. Pre-reform historical dates retain coarse precision unless explicitly converted.
Outbreak / comparison
A cluster of opportunistic pneumonia marks public recognition of AIDS
Region
United States / global epidemic
Agent or hazard
Human immunodeficiency viruses
Outbreak category
continuing global epidemic
Evidence and measurement
1981 is recognition, not origin; early case series is not the total epidemic burden.
Role of the event
outbreak / recognition

Sources

Related

On other timelines

Open A cluster of opportunistic pneumonia marks public recognition of AIDS in the timeline