According to research from University of Wisconsin-Madison, wild chimpanzees in Uganda have been stricken with two human respiratory viruses, parainfluenza virus 3 and metapneumovirus, which killed 25 chimps.

Parainfluenza virus 3 is a common cause of croup in preschool children. In people, metapneumovirus is a common cause of “wheezing illnesses” in infants, explains James Gern, a co-author of the new study and a professor of allergy and immunology in the UW School of Medicine and Public Health.

The outbreaks affected different chimp communities in the same forest at the same time, between December 2016 and February 2017, prompting suspicion that the outbreaks had a common cause.

One group, consisting of 205 chimpanzees known as the Ngogo community in Uganda’s Kibale National Park, was especially hard hit, with almost 44% of the animals in the group suffering from respiratory illness. Twenty-five chimps in the Ngogo group died during the outbreak.