US Deer Get COVID-19; What Are the Implications?

Whether you are a nature lover, environmentalist, hunter, or all of the above, you no doubt heard the news in early 2021 that the U.S. Department of Agriculture (USDA) found that as much as a third of tested white-tailed deer in Illinois, Michigan, New York, and Pennsylvania harbored COVID-19 antibodies.

Questions immediately ensued from the discovery: How did the deer get the virus? Could they transmit it to humans? And is their meat safe to eat?

As scientists investigated the COVID-19 variants harbored by the infected deer, more questions arose. While some strains resembled the Delta variant at the same time that Americans were experiencing Delta, other strains appeared to be the Alpha variant—which had long since waned in the United States. Why was it still active in deer? Were deer becoming U.S. COVID-19 reservoirs, keeping the virus alive?

A year after the USDA’s original discovery, COVID-19-exposed deer were found in 24 of 30 states sampled. In New York, white-tailed deer harbored the same variant as New Yorkers themselves—the Omicron variant. Adding to pandemic-related concerns, the variant found in deer in Canada exhibited 76 mutations that departed from the original Wuhan virus, including changes that increased the spike protein’s infectivity, reported Nature.

According to Colorado State University researchers, viruses adapt to the body temperature, diet, and immune system of whatever animal they are living in, which encourages such mutations. “It’s possible that the new [COVID-19] variants emerging in people could infect new animal species,” they wrote in a February article published on the university’s website. “Or it’s possible that new variants could initially arise from animals and infect humans.”

How Did Deer Contract COVID-19, and Can They Transmit It?

Scientists do not yet know how U.S. white-tailed deer came to harbor COVID-19, but it is known that the virus is transmitted between them, which seems to explain why it’s spreading. Did the deer drink water contaminated with COVID-19? Did it come from food given to them by humans, including hunters, who sometimes bait the animals? Did it come from minks, which are known to carry the disease? Could the virus have resulted from the deer “digging their noses into discarded masks, or gobbling flowers and garden vegetables that humans have sneezed on,” as Nature asked? Close to 30 million deer live in the United States—there’s one for every 10 people—and their habitats are increasingly urban as they commingle with people.

Scientists and hunting experts say that transmission to humans is unlikely because COVID-19 is airborne—though both recommend wearing face coverings when in close contact with deer. However, Juergen Richt, director of the Center of Excellence for Emerging and Zoonotic Animal Diseases at Kansas State University, warned that “if you as a hunter kill an animal, which is infected, and you got that animal, and you take out the lungs, etc., where the virus resides, there’s a chance that you [will] get infected,” according to the Topeka Capital-Journal.

Earlier this year, National Geographic reported news that was less reassuring regarding viral transmission: It looks like a deer-to-human transmission has been documented. A team of 32 academic and government researchers working in Canada found that a virus strain previously only found in deer had appeared in a human, and “that a person who had close contact with white-tailed deer in Ontario was infected with the same [deer] variant of coronavirus.”

“Together, those factors suggest that the virus had been circulating among deer and accumulated mutations as it hopped from one animal to the next, before ultimately being passed to a person,” the magazine reported.

Is Meat From Animals With COVID-19 Safe to Eat?

Worries about the transmission of COVID-19 to humans through eating meat surfaced early during the pandemic when slaughterhouse workers became sick and died from the virus. According to the Midwest Center for Investigative Reporting, in the few months from the start of the pandemic until April 2020, there had been “at least 86,000 reported positive cases tied to meat and poultry processing facilities from at least 499 outbreaks in 38 states, and at least 423 reported worker deaths in at least 67 plants in 29 states.” Worker outbreaks also occurred in Europe and Southeast Asia.

However, “there’s no indication that anyone has contracted [COVID-19] from eating any kind of uncooked food, including rare or raw meat,” Angela L. Rasmussen, a virologist at the Center for Infection and Immunity at the Columbia Mailman School of Public Health, told Forbes in 2020.

Nor should the surfaces of packages be feared, the Centers for Disease Control and Prevention (CDC) says. “Although some people who work in food production and processing facilities have gotten COVID-19, there is no evidence of the virus spreading to consumers through the food or packaging that workers in these facilities may have handled,” the agency wrote.

Still, the government recommendations for hunters handling deer that may contain COVID-19 or other diseases are off-putting:

• “Do not allow contact between wildlife and domestic animals, including pets and hunting dogs.”
• “Do not harvest animals that appear sick or are found dead.”
• “Keep game meat clean and cool the meat down as soon as possible after harvesting the animal.”
• “Avoid cutting through the backbone and spinal tissues and do not eat the brains of wildlife.”
• “When handling and cleaning game … wear rubber or disposable gloves.”
• “Cook all game meat thoroughly (to an internal temperature of 165 degrees Fahrenheit or higher).”

Another Deer Disease Affects Hunting

While the government guidelines may look extreme, they no doubt come from attempts to contain a different disease found in deer and elk called chronic wasting disease (CWD), which is more transmittable.

Similar to mad cow disease, CWD is a progressive, fatal “spongiform encephalopathy” (brain disease) transmitted by a misfolded protein called a prion. In humans, the condition is called Creutzfeldt-Jakob disease and is also fatal.

CWD is traced back to Department of Wildlife experiments in the mid-1960s on wild deer and elk at the Foothills Wildlife Research Facility in Fort Collins, Colorado, after which the first cases of CWD were noted. Transmitted by a rogue protein, or prion, CWD is now endemic in 30 states and affects white-tailed deer, black-tailed deer, mule deer, and elk.

States have instituted testing programs, and Outdoor Life urges hunters to honor them. “Participate in the fight [against CWD] by submitting every harvested deer for testing so the extent and location of the outbreak are better known. Stop the spread by learning about local and state carcass-transportation rules, and dispose of all deer carcasses appropriately in the zone where they were killed,” a January 2022 article by Outdoor Life reads.

To avoid catching Creutzfeldt-Jakob disease, Outdoor Life says to wait for test results before eating meat of any deer or elk “killed in a known CWD area,” and state government sources take the warnings a step further.

“Do not eat the eyes, brain, spinal cord, spleen, tonsils or lymph nodes of any deer,” the Illinois Department of Agriculture says, adding that you should avoid contact with “lymph nodes (lumps of tissue next to organs or in fat and membranes) as you work.”

In 2019, Food Safety News noted that there have been at least four cases of Creutzfeldt-Jakob disease in the United States since 1996. In 2002, a CDC Morbidity and Mortality Weekly report identified the disease in some Wisconsin men who “participated in wild game feasts.”

Human–Animal Contact Poses New Diseases

Certainly, deer aren’t the only animals who get and transmit COVID-19. Barbara Han, a disease ecologist at the Cary Institute of Ecosystem Studies, told NPR that as many as 500 species of animals share a version of the angiotensin-converting enzyme 2, or ACE2, receptor that helps COVID-19 enter cells. These possible animal hosts or reservoirs include many primates, bats, and carnivores such as red foxes and spotted hyenas, says Han. Humans have already been infected with COVID-19 by minks and hamsters, reports National Geographic.

Domestication, travel, agriculture, habitat fragmentation, urbanization, industrialization, and warfare have led to an unprecedented “geological period” that doesn’t bode well for future pandemics, write two researchers from the Netherlands. Researchers writing in the journal Genetics and Molecular Biology agree, noting that Middle Eastern Respiratory Syndrome or MERS, Ebola, SARS (the COVID-19 predecessor), and even HIV are viruses that originated from animals and jumped to humans.

While pandemics have seldom originated in the United States and deer are hardly an exotic species like camels (MERS) or apes (Ebola), their ability to catch and carry COVID-19 in the United States should not be ignored as the world attempts to pull out of the pandemic.

Follow

Martha Rosenberg is a nationally recognized reporter and author whose work has been cited by the Mayo Clinic Proceedings, Public Library of Science Biology, and National Geographic. Rosenberg’s FDA expose, “Born with a Junk Food Deficiency,” established her as a prominent investigative journalist. She has lectured widely at universities throughout the United States and resides in Chicago.