Researchers look into effects of COVID-19 variants on wildlife

There have been highly publicized cases of zoonotic diseases — illnesses that can be passed from animals to humans — in the news recently. While we’ve all learned a lot about epidemiology over the past couple of years, the scientific community is still collectively researching these viruses, in particular SARS-CoV-2, the virus that causes COVID-19 in humans. The origins and transmission pathways are still being investigated.

More research is needed to better understand the impact of new COVID-19 variants, the range of species that can be infected with SARS-CoV-2, effects in different animals, and how different species may carry or transmit the virus.

Canadian scientists recently released a study (which it is important to note has not yet been peer-reviewed or published in a professional scientific journal) that reports the first potential case of ‘reverse transmission’ of the SARS-CoV-2 virus from a deer to a human. According to study authors, the person who contracted the virus had recently been in contact with deer near Ontario, Canada and was infected with a strain very similar to the strain circulating in deer in the area.

While SARS-CoV-2 infection of white-tailed deer and other wildlife continues to be reported, there is no evidence that wildlife play a significant role in the spread among people. Evidence suggests it is much more likely for humans to spread the virus to deer, which then spread it to other deer. Researchers aren’t certain how the virus is spread from humans to deer, although studies are underway to better understand transmission pathways.

The COVID-19 variant reported in the Canadian study is considered a “highly divergent” variant — much different from those found in the past — including the Delta and Omicron variants circulating among humans now. However, preliminary analysis by researchers on this study suggests that COVID-19 vaccines still provide protection against this lineage of the virus and no evidence of other human cases in the region were identified by the researchers. They urge people not to be overly alarmed as, if confirmed, this would be the first case of deer-to-human transmission and the risk of contracting SARS-COV-2 from wildlife remains low.

To date, SARS-CoV-2 has only been found in wild white-tailed deer in the northeastern United States and central Canadian provinces. The U.S. Department of Agriculture (USDA) is working with some states in the east and mid-west on surveillance in white-tailed deer and other wildlife species. Washington could become involved in this or a similar study in the future but, as of now, does not have plans to implement such a program.

WDFW works closely with, and follows guidance from the Association of Fish and Wildlife Agencies (AFWA) regarding SARS-CoV-2 and free-ranging white-tailed deer.

Previously reported cases of transmission of SARS-CoV-2 from animals to humans have been identified in farmed mink. Conversely, there have been many reports of infected humans spreading the COVID-19 virus to other animals, such as pet dogs and cats and animals housed in zoos, after close contact. These reports highlight the importance of people with COVID-19 avoiding contact with animals to prevent spread of infection to household pets and captive or free-ranging wildlife, as well as the importance of basic recommendations to reduce the risk of disease exposure to humans while hunting, handling, or closely interacting with animals.

While deer hunting seasons are not currently underway, the Centers for Disease Control and Prevention (CDC) offers COVID guidance for people who hunt, trap, or handle wild animals. This guidance is very similar to the steps taken to help prevent catching COVID-19 from another human and includes wearing gloves, goggles, and a mask when there is the potential to be exposed to respiratory tissues and fluids, especially indoors, and to get vaccinated.

For those who have harvested a deer during past hunting seasons and are concerned about the risk of catching COVID-19 through consuming the meat, coronaviruses are killed by normal cooking temperatures and there is no evidence that cooked venison can spread the virus.

The CDC also has extensive information available on how to reduce your chances of contracting COVID from the most common source- other humans.