COVID-19 and Wild Animals

Experts believe the virus that caused the COVID-19 pandemic began in horseshoe bats. Since the start of the pandemic, scientists have wondered if this virus can spread from humans back to animals, and which types of animals could be at risk. It’s important that researchers study how COVID-19 affects wild animals to ensure their safety and protect humans from new flare-ups of the coronavirus.

How COVID-19 Affects Wildlife

In humans, the virus that causes COVID-19 binds to the ACE2 receptor in our cells. Experts looked at other animals’ ACE2 sequences and predicted which species are at risk for the virus as well. Their studies showed that several types of animals are at risk for COVID-19. This may include wild animals and animals in captivity (like in zoos or farms).

Testing wild animals is important to locate any new COVID-19 cases. In areas with managed wild animal populations, it’s crucial to control and stop the spread of the virus. Early detection will help experts find the source of the infection and learn more about how it spreads within these species.

Researchers have tested over 50 animal species in multiple zoos and aquariums. There have been cases of COVID-19 infections in animals like:

  • Big cats
  • Otters
  • Mink
  • Non-human primates
  • White-tailed deer
  • Spotted hyenas
  • Hippos
  • Ferrets
  • Bearcats (binturongs)
  • Coatimundis
  • Fishing cats

The number of confirmed species with COVID-19 continues to go up as the pandemic continues.

In zoos, experts haven’t seen any COVID-19 transmission from one managed species to another. All the infected animals got the virus from a human animal keeper who had COVID-19. Animals can become infected from contact with contaminated objects or surfaces, or aerosol (through the air) transmission.

But experts aren’t as concerned about COVID-19 outbreaks among animals in captivity. In these cases, animal caretakers can usually control the situation through quarantining, vaccination, or culling (selectively slaughtering animals). But it’s harder to control viruses when they occur in animals in the wild or farms or zoos.

Because of this, scientists around the world continue to study the risk of outbreaks in wild species. They constantly survey wildlife populations to catch an outbreak as soon as possible. Researchers test animals in zoos, homes, shelters, vet clinics, farms, and areas that surround these places. If they notice any positive COVID-19 cases, the country will alert the World Organization for Animal Health (OIE).

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Can Wild Animals Give Humans COVID?

Animals can spread SARS-CoV-2, the virus that causes COVID-19, to humans. But the risk is believed to be low.

While animal-to-human transmission isn’t a main concern in the COVID-19 pandemic, this could change in the future. After the global spread of COVID-19 in humans reduces, experts believe that wild animals with the virus could spark a new flare-up in people.

What Do We Know About COVID-19 in Mink?

Mink-to-human COVID-19 spread has been reported in the Netherlands, Denmark, and Poland. In the U.S., studies show there have been four cases of COVID-19 that likely can be traced to mink-to-human spread from a mink farm in Michigan. The CDC says this was expected, as this has been seen on other mink farms worldwide.

There’s an entire fur industry built around the controversial practice of farmers raising mink in captivity for their pelts. And on mink farms around the world, including in the U.S., there’ve been COVID-19 outbreaks.

Experts say these animals are prone to catching the disease from infected farm workers, and then COVID-19 spreads among the mink. It’s also possible for infected mink to spread the disease to people. But you probably don’t need to worry about this risk unless you work on a mink farm that’s having an outbreak.

Mink infected with COVID-19 might not show symptoms. But they could have mild to severe:

  • Coughing
  • Sneezing
  • Eye and nose discharge
  • Trouble breathing
  • Diarrhea

Farms with infected mink may also have more mink deaths than usual. The virus that causes COVID-19 may contaminate skins, pelts, and other goods made from infected mink.

What Do We Know About COVID-19 in Deer?

About 30 million white-tailed deer live in the United States, and people often come into close contact with them.

The CDC says there have been outbreaks in white-tailed deer in several states. Researchers say the deer were not sick, and at this time, the risk of spreading to humans is low.

Canadian researchers say they found possible lab evidence that a white-tailed-deer might have spread COVID-19 to a person in Ontario. The study hadn’t yet been peer-reviewed, meaning experts in the field hadn’t analyzed it.

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How Do We Know When Wild Animals Have COVID?

It can be hard to tell, and it depends on the animal. Some wild animals don’t have obvious symptoms. For instance, if you crossed paths with an infected white-tailed deer, you might not notice any clues that it has COVID-19.

Other wild animals can show signs that they’ve been infected. For instance, one study found that infected primates like Rhesus monkeys, crab-eating macaque, and marmosets can get fever, diarrhea, and pneumonia.

The only way to find out for sure if a wild animal has COVID-19 is for a wildlife health expert to give it a COVID test. In general, experts don’t recommend routine testing in free-roaming or captive North American wildlife species.

Why Is This Important for Human Health?

As COVID-19 spreads to different species, it adapts and mutates. Then, new types of the virus emerge. Over time, this can lead to variants that spread quicker or cause more severe illness. New types of the virus can influence the effectiveness of current COVID-19 therapies and vaccines. Since experts created these treatments to help earlier types of COVID-19, they may not work as well in the future if the virus continues to adapt and change.

Because of this, it’s very important to control any outbreaks, even if they’re in animal populations.

How to Keep Yourself Safe

While experts continue to study how COVID-19 affects animals, they do know that the risk of animal-to-human transmission is very low. There’s no need to harm or abandon wild animals out of fear of COVID-19.

But to be cautious, and to protect yourself from other possible diseases from wildlife animals, it’s important to take certain steps to reduce any risk of illness:

  • Don’t feed wild animals or touch animal droppings.
  • Keep yourself and your pets at a safe distance from wild animals.
  • Wash your hands after working or playing outside.
  • Don’t directly interact with orphaned animals. The parents usually return.
  • Don’t touch or get close to a sick or dead animal.
  • If you plan to eat legal game meat, read over your state’s wildlife agency guidelines.

WebMD Medical Reference Reviewed by Melinda Ratini, DO, MS on April 19, 2022

Sources

SOURCES:

BioRxiv: “Highly divergent white-tailed deer SARS-CoV-2 with potential deer-to-human transmission.”

Frontiers in Microbiology: “An Update on Animal Models for Severe Acute Respiratory Syndrome Coronavirus 2 Infection and Countermeasure Development,” “Spread of Mink SARS-CoV-2 Variants in Humans: A Model of Sarbecovirus Interspecies Evolution.”

Science: “Transmission of SARS-CoV-2 on mink farms between humans and mink and back to humans.”

USDA: “Questions and Answers: Results of Study on SARS-CoV-2 in White-Tailed Deer,” “Confirmed Cases of SARS-CoV-2 in Animals in the United States.”

National Geographic: “Hippos, hyenas, and other animals are contracting COVID-19.”

University of Southern California: “Scientists track the link between wildlife and COVID-19.”

Nature: “The search for animals harbouring coronavirus — and why it matters.”

Illinois News Bureau: “Which animals can catch the coronavirus?”

One Health Outlook: “Assessing the risks of SARS-CoV-2 in wildlife.”

CDC: “Handling Wildlife,” “Animals and COVID-19,” “Evaluation for SARS-CoV-2 Testing in Animals,” “Guidance for Safely Importing and Handling Mink and Mink Products to Prevent COVID-19.”

The Ohio State University College of Veterinary Medicine: “COVID-19 and Animals.”

National Geographic: “Government documents reveal CDC delayed disclosing likely COVID-19 animal spillover event.”

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