The first signs were the cough and runny nose.
After caretakers at the San Diego Zoo noticed a male snow leopard showing those symptoms on Thursday, they decided to have him screened for the coronavirus. Two tests of the animal's stool came back with the same results: positive.
Zoo officials are waiting for the U.S. Department of Agriculture to confirm the infection. But they said in a Friday statement they are closely monitoring the snow leopard, a 9-year-old named Ramil. The species is considered vulnerable to extinction, with the International Union for the Conservation of Nature estimating there are 2,700 to 3,300 mature snow leopards left in the wild.
"I know that this cat is going to get the best possible care," Chief Conservation and Wildlife Health Officer Nadine Lamberski said in a statement provided by the zoo. "And I'm confident that the team has the expertise to manage this situation."
So far, Ramil appears to be "doing well," the statement said, with just the cough and runny nose as symptoms. Veterinarians assume the animals that share his habitat - a female snow leopard and two Amur leopards - have also been exposed, so all are being quarantined. Their exhibit is closed to visitors until further notice.
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Ramil had not yet been vaccinated against covid-19. Staff began administering doses of an experimental vaccine made specifically for animals in March, after an asymptomatic keeper wearing protective gear unknowingly spread the virus to the zoo's gorilla troop.
The eight gorillas recovered within weeks, but the experience convinced zoo officials to take action to protect the animals at the highest risk of infection. The virus has been shown to infect mammals, the Centers for Disease Control and Prevention said, with multiple reports of companion and zoo animals becoming sick. Most got the virus after contact with infected humans.
Among the animals that tested positive for coronavirus: four tigers and three African lions at New York's Bronx Zoo, two tigers at the Fort Wayne Children's Zoo in Indiana, two tigers at Norfolk's Virginia Zoo and three snow leopards at the Louisville Zoo in Kentucky.
In light of such infections, some zoos turned to the experimental animal vaccine. Zoetis, a New Jersey-based veterinary pharmaceutical company, donated doses to zoos across the country, including San Diego's. Four orangutans and five bonobos at the zoo became the first nonhuman primates to be vaccinated against the virus.
"We've been vaccinating animals almost daily," Lamberski said. "We're doing it as quickly and as responsibly as possible."
The zoo also stepped up health and safety protocols at the start of the pandemic, providing N95 masks to staff, requiring unvaccinated zoo employees to wear masks and following cleaning and disinfecting protocols. Guests who are not vaccinated are asked to wear masks and maintain social distance, and Lamberski said zoo officials are encouraging employees to get the shots "to protect themselves and our wildlife."
It's not clear how Ramil became sick. But Lamberski said his infection demonstrated "the interconnectedness of the health of wildlife, people and the environment."
"It's all interconnected," she said, "and what affects the health of one affects the health of all."