Virus Risk for Animals in Covid-19

Concerns about the Virus spreading through animal populations have been reignited by two studies that found significant levels of Covid-19 infection in wild deer in the United States. The findings, which were published this month, coincide with an increase in reports of Covid in pets and confined animals. The sickness claimed the lives of three endangered snow leopards at the Lincoln Children’s Zoo in Nebraska earlier this month.

Despite the fact that the Sars-Cov-2 Virus causes few or no symptoms in most non-human animals, some scientists are concerned that wildlife could become a reservoir of infection — and even viral mutation — that could be passed on to humans. It may potentially pose a threat to endangered species.

Up until the end of October, the World Organisation for Animal Health (OIE) had registered 598 Covid outbreaks in animals affecting 14 species in 30 countries. Almost all of the outbreaks have included captive animals in close proximity to humans, with farmed mink in Denmark being the most afflicted. Because there has been little testing, no one knows how common Covid is in wildlife. The two new investigations of wild white-tailed deer in the United States are the first to reveal widespread illness.

Early this year, scientists from the US Department of Agriculture released an article in PNAS that showed antibodies to Sars-Cov-2 in 40% of wild white-tailed deer in four US states. A second study, sponsored by Penn State University and not yet published, found the Virus in 80% of samples taken in Iowa from the same species — the most numerous deer in North America with an estimated 30 million individuals — using PCR testing. Multiple spillovers from sick humans, followed by broad transmission from deer to deer, according to genetic and geographic data.