Nine big cats at the National Zoo in Washington have tested positive for the coronavirus, which causes Covid-19, the Smithsonian Institution said Friday.
Animal caretakers observed appetites, coughing, sneezing and lethargy in six African lions, a Sumatran tiger and two Amur tigers, and final results were expected in coming days to confirm the presumptive positive coronavirus test results, said the Smithsonian, which operates the zoo.
"All lions and tigers are being treated with anti-inflammatories and anti-nausea medication to address discomfort and decreased appetite," the zoo said on its website, adding that they were also being treated with antibiotics for possible secondary bacterial pneumonia.
The big cats will remain in their indoor-outdoor habitats, posing no risk to visitors because of the "substantial distance between the animals and visitors," zoo officials said.
No other animals were showing coronavirus symptoms, but an experimental veterinary coronavirus vaccine would be distributed to animals deemed at risk of disease, it said.
Zoo officials said they did not know how the animals became infected and pointed out that staff members wear masks around the animals.
Outbreaks among animals kept in cramped quarters on fur farms led to the culling of thousands of minks in Denmark in 2020.
Scientists have known for over a year that pets can catch coronavirus from humans, and cats appear more susceptible than dogs. Lions and tigers were singled out as particularly at risk of disease in 2020 because many are kept captive at unregulated zoos and private residences.