The animals are the first at the Denver Zoo to test positive.

On Friday, officials with the Denver Zoo announced that two Amur tigers, Yuri and Nikita, have tested positive for coronavirus.

Both 11 years old, the tests were tested with swab samples that were sent to the Colorado State University Veterinary Diagnostic Laboratory in Fort Collins after they'd been seen coughing, sneezing, and exhibiting other signs of COVID-19.

Those results were then confirmed by the United States Department of Agriculture's National Veterinary Services Laboratories.

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

This comes months after several animals at the Denver Zoo received the COVID-19 vaccine, which was developed specifically for animals.

Neither tiger has been vaccinated against COVID-19, however. The zoo's veterinarians do plan to vaccinate them, along with other big cat species, as soon as more doses of the animal-specific Zoetis vaccine become available.

"Yuri and Nikita will remain under close observation by their keepers and veterinarians, and receive treatment for any symptoms as needed," said the Denver Zoo. "Both tigers will continue to have access to their outdoor habitats, however there is no risk to public health due to the distance between guests and the animals. Daily tiger demonstrations have been suspended until Yuri and Nikita fully recover."