COVID-19 may have potential to spread between wildlife

Animals becoming infected with SARS-CoV-2 after coming into contact with people positive for COVID-19 have been documented around the world.

Since last year, reports of animals in zoos having COVID-19 made headlines, including an outbreak between lions and tigers at the Bronx Zoo in New York City.

The CDC states, “Most of these animals became infected after contact with people with COVID-19, including owners, caretakers, or others who were in close contact.”

Though all of the animals which could contract the virus is not known, the CDC states the following have been reported as being infected.

• Companion animals, including pet cats and dogs and one ferret.
• Animals in zoos and sanctuaries, including several types of big cats, otters, and non-human primates.
• Mink on mink farms.
• Wild white-tailed deer in several U.S. states.

Mink have been confirmed to have spread the virus between other mink, as well as dogs and cats.

“Mink-to-human spread of SARS-CoV-2 has been reported in the Netherlands, Denmark, and Poland, and new data suggest it might have occurred in the United States,” states the CDC.

An investigation at a mink farm in Michigan showed people infected with a variant containing “mink-related mutations”. The finding suggests the transfer of the virus from mink to human may have occurred, though this has not yet been confirmed.

A recent study shows the potential for reverse zoonosis, the spreading of the virus from human to wildlife.  The study evaluated 624 pre and post pandemic serum samples from white-tailed deer in various populations. Antibodies were discovered in 152 of those samples, suggesting the deer in those areas were exposed to COVID-19.

The CDC states, “Recent experimental research shows that many mammals, including cats, dogs, bank voles, ferrets, fruit bats, hamsters, mink, pigs, rabbits, racoon dogs, tree shrews, and white-tailed deer can be infected with the virus. Cats, ferrets, fruit bats, hamsters, racoon dogs, and white-tailed deer can also spread the infection to other animals of the same species in laboratory settings.”

The CDC also states the findings do not show if the infected animals can spread the virus back to the human population. “Many studies have been done to learn more about how this virus can affect different animals. These findings were based on a small number of animals, and do not show whether animals can spread infection to people.”