Humans transmit more viruses to domestic and wild animals than we contract from them. Most emerging and re-emerging infectious diseases are caused by viruses circulating in animals.
When they move from vertebrate animals to humans, a process known as zoonosis, they can cause outbreaks of diseases such as avian flu or Covid-19. The close interaction between men and animals, added to the increase in commercial activity and mobility, is favoring the greater spread of zoonoses, says researcher Cedric Tan.