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• Posted April 15, 2026

Wildlife Trade Tied To Higher Risk of Diseases Spreading to Humans

Buying or selling wild animals, whether for food, pets or other uses, may increase the risk of diseases spreading to people, a new study finds.

Researchers looked at more than 40 years of global wildlife trade data and thousands of mammal species. They found that animals involved in the trade were 50% more likely to carry germs that can infect humans.

“There’s no safe trade,” study author Jérôme Gippet, an ecologist at the University of Fribourg in Switzerland, told The New York Times. “As long as we continue trading species, we will expose ourselves to this problem.”

The study — published April 9 in the journal Science — identified more than 2,000 traded mammal species, or about a quarter of all mammal species on Earth.

Researchers found that 41% of the species that are traded carried at least one pathogen that's known to infect humans. On the other hand, only 6% of species not involved in trading shared any pathogens with people.

The longer a species was traded, the higher the risk. For every 10 years a species appeared in trade records, The Times said, it shared an additional pathogen with humans, researchers found.

These zoonotic pathogens cause include Ebola, mpox and Salmonella. 

Some past outbreaks have been linked to wildlife trade, and some scientists believe SARS-CoV-2, the virus that causes COVID-19, may have first spread to humans at a live animal market.

“The more species are traded, the more opportunities they will have to transmit pathogens to humans,” Gippet explained.

Live animal markets and illegal wildlife trade may raise the risk even more, allowing pathogens to jump between animal species.

“What you get are steppingstones, where viruses are evolving in these markets,” study co-author Colin Carlson, a global change biologist at Yale University, told The Times. “Maybe they’re able to adapt to humans for the first time.” 

Ann Linder, an associate director at the animal law and policy program at Harvard Law School who was not involved in the study, reviewed its findings.

“The study’s authors demonstrate through data what we’ve long suspected to be true — that human use and exploitation of wildlife actually increases the risks of spillover,” she said. 

“Wildlife, left alone in intact ecosystems, pose very little risk of spreading zoonotic disease to people,” Linder said.

But more data is needed, she emphasized.

“We’re really not able to speak with any kind of certainty about the size and scale of the trade itself,” Linder said. “We need more studies like this, but, perhaps more fundamentally, we need more and better data to even begin to understand our own risk.”

More information

World Wildlife Fund has more on efforts to reduce zoonotic disease risk from wildlife trading.

SOURCE: The New York Times, April 14, 2026