Humans’ exploitation of wildlife is directly causing more viruses to spillover from animals to people, according to a new study published Wednesday in Royal Society Publishing.
The research was carried out years before the coronavirus outbreak, which is believed to have originated in Wuhan, China, and has infected more than 1.5 million people worldwide and killed more than 87,000, according to data from Johns Hopkins University.
"Viruses jump species when there is close enough contact to enable transmission between an infected animal and a susceptible person. Animals in close contact can share viruses with humans by respiratory droplets, or contact with feces, urine or blood," epidemiologist Christine Johnson from the University of California Davis told Newsweek.
Coronaviruses are zoonotic, meaning they are transmitted between animals and people. They can be caused by parasites, bacteria, fungi and viruses.
In the study, scientists from Australia and the U.S. found that spillover risk was highest from threatened and endangered wild animals whose populations declined largely due to loss of habitat, hunting and the wildlife trade. The researchers also found that species in the primate and bar orders were “significantly more likely to harbor zoonotic viruses compared to all others.”
Researchers examined 142 zoonotic viruses using 2004 to 2013 data from an internationally recognized authority on threatened species.
Domesticated mammals, including pigs, cattle, horses, sheep, cats and dogs, host 50 percent of the viruses that can be passed to mankind, while rodents, bats and primates together were implicated as hosts for nearly 75 percent of all viruses.