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SAN DIEGO — Sumatran tigers are the third species at the San Diego Zoo and Safari Park believed to have been infected with COVID-19.

News of the suspected cases in the group of tigers came less than a week after a second snow leopard was said to be infected, and a troop of gorillas also suffered from the virus in January. Here’s what we know as the zoo works to vaccinate all of its susceptible animals.

Gorilla troop tests positive

The first cases of COVID-19 in animals at the parks were announced in January. Veterinarians tested a troop of gorillas at the Safari Park for COVID-19 after some showed symptoms, including mild coughing, congestion, nasal discharge and intermittent lethargy.

It was believed the gorillas caught the infection from an asymptomatic staff member despite precautions, including PPE worn by staff when near the primates.

The zoo later confirmed the gorillas were infected with the B.1.429 variant of the coronavirus, which was prevalent in California at the time. The troop made a full recovery and the zoo said their diagnosis was the first known instance of the virus being naturally transmitted to apes.

Two snow leopards show symptoms

On July 23, the zoo revealed a 9-year-old male snow leopard named Ramil was suspected to be positive for COVID-19. Wildlife care specialists noticed he had a cough and nasal discharge, and a second snow leopard, a 3-year-old female named Naphisa, tested positive for the virus around July 29.

How the two snow leopards were exposed to the virus has not yet been revealed. The two leopards along with two Amur leopards who share their habitat were quarantined as a group.

Sumatran tigers in quarantine

The latest suspected cases in animals were announced on Aug. 3. The Safari Park said its Tiger Trail exhibit was closed because of suspected cases in a group of six Sumatran tigers.

Veterinarians said some of the six tigers were suffering from a cough and an in-house COVID-19 PCR test yielded a positive result from fecal samples. The tigers are quarantining in their habitat as the Safari Park awaits confirmation of the test results by the National Veterinary Services Laboratory.

The zoo is still looking into how the animals were exposed.

COVID-19 vaccines for animals

Great apes at the San Diego Zoo were some of the first animals in our area to receive doses of a COVID-19 vaccine made strictly for animals.

Four orangutans and five bonobos got the Zoetis COVID-19 vaccine in February. A spokesperson said the previously-infected gorillas didn’t receive the vaccine because experts believed they developed their own immune response.

The San Diego Zoo Wildlife Alliance said Tuesday that staff has been working as fast as they can to vaccinate all susceptible species at both parks, including lions, tigers, leopards, cheetahs, jaguars, mountain lions, servals, ocelots, caracals, black-footed cats and sand cats. Other species expected to be vaccinated include primates like vervet monkeys, hamadryas baboons, geladas, colobus monkeys and siamangs; mustelids like otters and carnivores such as hyenas and dholes.

The zoo said many animals already had or were scheduled to receive their first vaccine within the coming days.

The Oakland Zoo was also vaccinating its large cats, bears and ferrets against the coronavirus using the experimental vaccine donated to zoos, sanctuaries and conservatories across the country.