Denver Zoo records first known COVID cases in hyenas

Two hyenas at the Denver Zoo tested positive for the coronavirus, a US veterinary lab announced on Friday.

They are believed to be "the first hyenas confirmed with COVID-19 worldwide," according to officials.

Anthrax-proof hyenas likely not at risk, zoo says

The two hyenas in question are 22-year-old Ngozi and 23-year-old Kibo in captivity in the western US state of Colorado. 

In a statement on Twitter, zoo officials said the hyenas were experiencing "extremely" mild symptoms, including "slight lethargy, some nasal discharge and occasional coughs."

"Hyenas are famously tough, resilient animals that are known to be highly tolerant to anthrax, rabies and distemper", said zoo officials. "They're otherwise healthy and expected to make a full recovery."

All of the zoo's 11 lions and two of its tigers also tested positive for the virus. As of November 3, the two tigers were declared clear of the virus, zoo officials said in a statement.

While all of the zoo's lions were still testing positive, zookeepers said their symptoms "are improving."

How has the zoo reacted?

According to a statement from the United States Department of Agriculture's National Veterinary Services Laboratories (USDA NVSL), coronavirus infections have been reported in multiple animal species worldwide.

In most cases, these have been animals in close contact with a person with COVID-19.

"We've known for a while what species at the zoo are susceptible to the virus, and we've taken every necessary precaution to protect our animals," Brian Aucone, senior vice president for life sciences at the Denver Zoo, said in an earlier statement.

Zoo staff are required to adhere to strict COVID-19 protocols around the animals, including the use of personal protective equipment.

None of the animals had been vaccinated against COVID-19, but Denver Zoo veterinarians are planning to vaccinate them once more doses of the animal-specific Zoetis vaccine are available.

Tips for preventing animals from getting COVID

Based on current information, the risk of most animals spreading the virus to humans is low — although animals can contract the coronavirus from humans.

The NVSL recommends that those infected with COVID-19 avoid contact with animals, including pets.

According to the Associated Press, the NVSL not only functions within the US, but also serves as an international reference lab — providing testing for foreign and emerging diseases in animals.