Special Report

Worst Outbreaks of All Time

Source: Ian Brodie / Express / Getty Images

20. Hong Kong Flu
> Death toll: 1 million
> Disease/Cause: H3N2 strain of the Influenza A virus
> Affected area: Asia, Australia, Europe, United States
> Duration: 1968-1969

The Hong Kong flu was caused by an H3N2 influenza virus that spread to other continents in 1968. It is still in circulation. The severity of the flu varied by region. It affected few people in Japan but was more widespread in the United States. The most susceptible groups, babies and older people, died at higher rates. A vaccine created to fight the virus became available only after the flu had peaked. Influenza is a contagious respiratory illness caused by influenza viruses.

Source: Public Domain / Wikimedia Commons

19. Third Cholera Pandemic
> Death toll: 1 million
> Disease/Cause: Cholera
> Affected area: Originated in India, spread through Asia, Europe, North America, and Africa
> Duration: 1852-1860

England was in the grip of the pandemic — which originated in India and spread to many continents — when physician John Snow, one of the fathers of modern epidemiology, conducted the research that would eventually lead to the conclusion that cholera is waterborne. He also traced a local cholera outbreak in a London street to a specific water pump. Cholera is a diarrheal illness caused by an infection of the intestine by the bacterium vibrio cholerae and can lead to dehydration and death if left untreated.

Source: Courtesy of U.S. National Library of Medicine

18. Russian Flu
> Death toll: 1 million
> Disease/Cause: Influenza A virus subtype H2N2
> Affected area: Turkestan, Canada, Greenland
> Duration: 1889-1890

The Russian flu outbreak in the 19th century is noteworthy because it was the first major epidemic to strike Europe after railroads were laid down. In 1889, there were already more than 125,000 miles of rail lines connecting European cities, allowing for easier spread of disease.

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17. Tuberculosis Outbreak
> Death toll: 1.3 million
> Disease/Cause: Tuberculosis
> Affected area: Worldwide
> Duration: 2012

Tuberculosis, an infectious bacterial disease, killed 1.3 million people worldwide in 2012. The disease infects one-third of the world’s population. In the United States, there has been greater success in controlling the disease. Only 3.2% of the American population is estimated to have tuberculosis. According to the National Institutes of Health, there are only 11,000 cases per year of tuberculosis in the United States.

Source: Public Domain / Wikimedia Commons

16. Sixth Cholera Pandemic
> Death toll: 1.5 million
> Disease/Cause: Cholera
> Affected area: Middle East, North Africa, Eastern Europe and Russia
> Duration: 1899-1923

The sixth cholera pandemic began at the end of the 19th century in the Indian province of Bengal and killed more than 800,000 in India before moving to the Middle East, northern Africa, Russia, and parts of Europe.