By Carlyn Kranking
Medill Reports

Some of the largest pandemics in history, including HIV/AIDS, Ebola and COVID-19, started in animals and then passed to humans. For the last century, about two viruses per year have passed, or “spilled over,” from animals to people.

These diseases are known as “zoonotic.” But just because they come from animals doesn’t mean it’s the animals at fault. Human activity is making it easier for zoonotic diseases to spread. As people destroy habitats, transport live animals to market, raise large numbers of livestock in close confinement and change Earth’s climate, it brings animal populations and their infections closer to humans.

This infographic explains these four “drivers” of pandemics and offers potential solutions to help limit the risk of pandemics in the future.

Carlyn Kranking covers health, environment and science at Medill. You can follow her on Twitter at @carlyn_kranking.