Human encroachment into animal habitats is increasing the risk of new infectious diseases such as Covid-19, a major new study has said.
Researchers from the US and Australia found that domesticated species, primates, bats and rats accounted for the vast majority of zoonotic diseases - those which transfer from animals to humans and account for 70 per cent of all human pathogens.
But it also found that hunting, the wildlife trade and the conversion of land for agriculture was increasing the interaction of humans with wild animals and with it the risk of disease transmission.
The study, published in the journal Proceedings of the Royal Society B looked at 142 zoonotic viruses and cross-referenced them with the IUCN Red List of Threatened Species.
Among threatened species, the researchers found that those who were at risk of population decline because of the wildlife trade and hunting had twice as many zoonotic viruses as those that are under threat from other sources. The researchers hypothesise that this could be the result of the increased interaction between humans and animals.
The study also found that animals whose habitat was under threat, likely from deforestation and the conversion of land from agriculture, were twice as likely as other threatened species to be found carrying zoonotic diseases.
It concludes that “the causes of wildlife population declines have facilitated the transmission of animal viruses to humans”.
"Our data highlight how exploitation of wildlife and destruction of natural habitat in particular, underlie disease spillover events, putting us at risk for emerging infectious diseases," Christine Johnson, from the University of California's School of Veterinary Medicine and lead author of the research, told AFP.
Rodents, bats and primates were found to be the source of 75 per cent of zoonotic species. Domestic species, particularly pigs, cows, horses and sheep, were found to have eight times more zoonotic viruses than wild mammalian species.
The novel coronavirus that causes Covid-19 is believed to have originated in bats, which have been carriers for other coronaviruses, as well as Ebola and the Nipah virus.
Its path to humans is unclear but may have been via an intermediary animal such as a pangolin at an animal market in China.
Beijing has since temporarily banned its wildlife markets, and the World Health Organisation is under pressure to call for an end to the practice worldwide.
Last year the UN warned that up to one million species are at risk of extinction thanks to human activity.
"Once we move past this public health emergency, we hope policy makers can focus on pandemic preparedness and prevention of zoonotic disease risk, especially when developing environmental, land management, and animal resource policies," Ms Johnson told AFP.