The Ebola outbreak that was first reported in March 2014 has infected more than 28,000 people, with more than 11,300 deaths.

Pandemics are generally defined as epidemics that occur over a wide area, crossing international boundaries and affecting a large number of people. Following are some of history’s largest pandemics, with their estimated death tolls.

Compiled by Jennifer Shyue ’17

Getty Images: ullstein bild

Plague of Justinian 
Byzantine Empire
Bubonic plague
25 million

Getty Images: Hulton Archive

Black Death
Europe
Bubonic plague
75–200 million

Getty Images: Culture Club

Third Plague Pandemic
China/India and beyond
Bubonic plague 
12 million

Getty Images: PhotoQuest

1918 Flu Pandemic
Worldwide
H1N1 influenza virus
24–40 million

Getty Images: Photofusion

HIV/AIDS
Worldwide
HIV
39 million

Sources: Centers for Disease Control; World Health Organization; Wikipedia; The New York Times