Growing reports that white-tailed deer have been infected by SARS-CoV-2 and that some have been sick with COVID-19 in addition to ongoing illnesses and infections in animals and pets at zoos has sparked concerns among certain experts that animals could become reservoirs for the development of new variants or even direct transmission from animal to human.
As of now, it’s generally been humans who have contracted the virus, but sometimes, the reason for the infection is not clear.
Three snow leopards at the Lincoln Children’s Zoo in Nebraska recently died due to COVID-19 related complications. Two tigers at the zoo also caught the virus in October but have since recovered.
The same happened at the Smithsonian National Zoo, Washington, DC in September, when six African Lions and a Sumatran Tiger were tested positive for COVID-19. Zoo personnel were unable identify the cause of the infections.
The US Department of Agriculture reported in July that antibodies against SARS-CoV-2 were found in white-tailed Deer in Illinois, Michigan and New York. This indicated that the animals had been infected.
The agency also announced that it had found actual signs of the virus in Ohio deer during its August sampling.
Recently, Penn State University researchers in November published a preprint study that showed increasing numbers of deer in Iowa had tested positive and could be a sign of the transmission of deer-to human.
Humans Infecting Animals
Angela Bosco–Lauth, PhD., DVM, assistant professor of biomedical sciences at Colorado State University, Fort Collins, Colorado, stated that humans are the most likely carriers of disease among deer.
She noted that deer that infect humans is less likely than the other alternative. “The likelihood of a human contracting the disease from a deer they’ve just shot is pretty minimal,” Bosco-Lauth told Medscape Medical News.
She said that it cannot be completely eliminated. With SARS-CoV-2 “what we’re experiencing is unprecedented in the history of medicine,” said Bosco-Lauth, noting the massive amount of infections around the world.
She said that it is more worrying to consider the possibility of a new variant, especially in animals that are farmed and domesticated. “We’ve seen with Delta and other variants that mutations can occur quite easily and are host-adapted.”
Bosco-Lauth along with her coworkers recently conducted research on dogs, cats, and hamsters to study the evolution of SARS-2 in these animals. They discovered that the virus changed rapidly in the hosts of these animals, especially in dogs and cats.
The authors suggested in their study published earlier this month in the Proceedings of the National Academy of Sciences, that the development of SARS-CoV-2 among companion animals and other potential animal hosts should be monitored closely.
Bosco-Lauth declared that cats are especially susceptible to COVID-19 infections and are near to humans. “That seems like an ideal location where you might witness transmission back-and-forth between humans and animals, and possibly variants arising from the transmission.”
The US Centers for Disease Control and Prevention declares that humans are able to spread COVID-19 to animals including domestic pets, animals that are farmed such as mink and zoo animals, however the agency stresses that there’s no evidence COVID-19 can spread from animals to humans apart from farmed mink.
Denmark has killed millions of mink in 2020 to ward off a mutation that was triggered due to animal-to-human and human-to-animal transmission. Denmark also burned 4 million of the mink killed after they began to resurface from mass burial sites earlier this year.
Hunters are Recommend to Take Caution
SARS-CoV-2 cannot be transmitted via blood. It is a respiratory condition. There is no evidence to suggest that anyone is at risk of contracting the disease by eating deer meat. However certain states are warning hunters to be extra careful when field dressing whitetail deer.
The majority of experts recommend that hunters adhere to the guidelines of the CDC to handle wildgame. This includes not cutting through the backbone or spinal tissues and not eating wild animal’s brains.
Wisconsin has suggested wearing a mask. It recommends hunters to avoid cutting or handling of the throat, lungs and the nasal cavity of the mouth.
Massachusetts recommends wearing a face shield in addition to the CDC guidelines. A Rhode Island state wildlife biologist said in the Providence Journal that he’d advise wearing a mask while field-dressing deer.
A quick glance at state hunting guidelines shows that most recommend the COVID-19 vaccine to protect against infection from any animal source.
Extra precautions are never ill-advised, said Bosco-Lauth and said it’s “a good idea to wear a face mask to protect yourself from other pathogens that could cause illness in addition to SARS-CoV-2.”
Alicia Ault, a Lutherville Maryland-based freelance journalist, has been featured in publications like JAMA, Smithsonian.com and the New York Times. You can find her on Twitter @aliciaault.
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