Humans give more viruses to animals than they give us, study finds

WASHINGTON: Some of the deadliest diseases to stalk humankind have come from pathogens that jumped from animals to people. The virus that causes AIDS, for example, crossed over from chimpanzees. And many experts believe the virus that caused the Covid-19 pandemic flowed from bats.

But, as a new study shows, this exchange has not been a one-way street. An analysis of all the publicly available viral genome sequences yielded a surprising result: humans give more viruses - about twice as many - to animals than they give to us.

The researchers looked at nearly 12 million virus genomes and detected almost 3,000 instances of viruses jumping from one species to another. Of those, 79 percent involved a virus going from one animal species to another animal species. The remaining 21 percent involved humans. Of those, 64 percent were human-to-animal transmissions, known as anthroponosis, and 36 percent were animal-to-human transmissions, called zoonosis.

The animals affected by anthroponosis included pets such as cats and dogs, domesticated animals such as pigs, horses and cattle, birds such as chickens and ducks, primates such as chimpanzees, gorillas and howler monkeys, and other wild animals such as raccoons, the black-tufted marmoset and the African soft-furred mouse.

Wild animals in particular were much more likely to experience human-to-animal transmission than the other way around.