What are zoonoses?
One of those researchers, wildlife veterinarian and microbiologist Fabian Leendertz, who helped trace the initial Ebola infection back to bats that lived in a hollow tree where children played, joins the WHO team on its mission in China.
Leendertz's research helped experts understand how the disease had spread and the risk posed by close contact with these animals.
While identifying that first case was important in curbing Ebola, the detective work was made much easier because of how lethal and unique Ebola is, says Martin Beer, a professor of virology at the Federal Research Institute for Animal Health in Germany.