The past couple of years have highlighted the risk of dangerous viruses jumping from animals to people. But an international study has shown that people transmit plenty of viruses to animals, too.

The study identified more than 100 examples of viruses spilling over from people to wild animals, like the spread of the coronavirus that causes COVID-19 from humans to mink, deer and big cats. Nearly half of these cases involved animals in zoos, particularly viral transmission from humans to other primates. This could have a significant impact on vulnerable species.

Disease spread to animals may also provide a viral melting pot, of sorts, allowing for new variants to develop and spill back over to people. So, keeping a close eye on cross-species transmission is crucial for people and animals alike.