Dozens of Mammals Could be Susceptible to the Coronavirus, Study Shows

Many great apes and farm animals could be affected, researchers say.

Sheep in pen
A number of farm animals, including sheep, horses, and pigs, may be susceptible to the coronavirus, researchers say. Holly Hildreth / Getty Images

More than two dozen animals that are in regular contact with people may be vulnerable to SARS-CoV-2, the virus that causes COVID-19, a new study suggests.

The study, which models how the virus might infect different animals' cells, found evidence that 26 animals may be susceptible to infection by the virus. 

For the study, researchers from University College London studied how the spike protein from SARS-CoV-2 could interact with the ACE2 protein it attaches to when it infects people.

They investigated whether mutations in the ACE2 protein would change the stability of the binding complex between the virus protein and the host protein. Researchers analyzed mutations in 215 animals. 

To gain entry into the host cells, the virus must bind to the protein. Scientists say that it’s possible the virus might be able to infect animals through another pathway, but current evidence suggests it’s unlikely if it cannot form a stable binding complex with ACE2.

The study found that for some animals — such as sheep and great apes — the proteins would be able to bind together just as strongly as when the virus infects people.

Great apes include chimpanzees, gorillas, orangutans, and bonobos. Many of these species are already endangered in the wild, so being susceptible to the coronavirus could add another level of risk to their survival.

26 animals at risk of coronavirus infection
Researchers found 26 animals at risk of infection. Numbers represent the change in binding energy of ACE2..  Lam, S.D., Bordin, N., Waman, V.P. et al.

Other animals that could potentially be affected include horses, goats, pigs, cows, and rabbits.

The researchers point out that some of these animals, such as sheep, have not yet been researched, so this study does not confirm that they can indeed be infected.

The study was published in Scientific Reports.

"We wanted to look beyond just the animals that had been studied experimentally, to see which animals might be at risk of infection, and would warrant further investigation and possible monitoring,” said lead author Christine Orengo, a UCL professor of structural and molecular biology, in a statement.

"The animals we identified may be at risk of outbreaks that could threaten endangered species or harm the livelihoods of farmers. The animals might also act as reservoirs of the virus, with the potential to re-infect humans later on, as has been documented on mink farms."

The findings are mostly consistent with research conducted on animals and with reported cases of animal infections. They include predicted possible infection in domestic cats and dogs, as well as mink, lions, and tigers, all of which have already been reported. They also suggest cases in ferrets and macaques, which have been infected in laboratory research.

In the U.S. alone, dogs, cats, mink, a lion, and a tiger have all tested positive for the coronavirus.

In this new study, researchers also performed a more in-depth analysis to see how the infection risks may differ across species. Their findings suggest that most birds, fish, and reptiles are likely not at risk of infection, but the majority of the mammals they studied could potentially be infected.

"To protect animals, as well as to protect ourselves from the risk of one day catching COVID-19 from an infected animal, we need large-scale surveillance of animals, particularly pets and farm animals, to catch cases or clusters early on while they're still manageable,” said co-author Co-author Professor Joanne Santini, a UCL professor of structural and molecular biology. 

"It may also be important to employ hygiene measures when dealing with animals, similar to the behaviours we've all been learning this year to reduce transmission, and for infected people to isolate from animals as well as from other people."