The Antonine Plague, 165-180
5 Million
The Justinian Plague, 541-542
25-50 Million
The Black Death, 1347-1351
75-200 Million

Illustration of the Plague in 1348 Florence.
Photo Credit: Wikimedia Commons
Smallpox, 1520
8 Million

Illustration of Aztecs suffering from smallpox as shown in the 16th century Florentine Codex.
Photo Credit: Wikimedia Commons
The Cocoliztli Epidemic, 1545
12-15 Million
The Third Cholera Pandemic, 1846-1860
Over 1 Million
Trench Fever, 1914-1918
3 Million

Soldiers on the Belgian Front are deloused to prevent trench fever.
Photo Credit: Wikimedia Commons
The Spanish Flu, 1918-1919
17-100 Million
The Asian Flu, 1957-1958
1-2 Million
The Hong Kong Flu, 1968
1-4 Million
The HIV/AIDS Crisis, 1981-1995
Over 30 Million

ACT UP activists at the "Storm the NIH" protest movement in 1990.
Photo Credit: NIH History Office / Flickr (Public domain)