Six lions and three tigers at the National Zoo in Washington have tested positive for Covid-19 and are undergoing treatment after falling unwell, the zoo said Friday.
"Last weekend, animal keepers observed decreased appetites, coughing, sneezing and lethargy" in six African lions, a Sumatran tiger and two tigers from Siberia, who all tested positive for Covid in preliminary tests, the zoo said in a statement.
Results of tests to confirm the diagnosis are expected in a few days.
The sick cats are being treated with anti-inflammatories and anti-nausea medication, as well as antibiotics to ward off pneumonia.
People who visit the zoo are not at risk because of the distance between them and the felines, and no other animals have shown signs of infection, the zoo said.
The bout of sickness comes as several US zoos including the one in Washington announced Tuesday the launch of a vaccination campaign for animals susceptible to Covid-19.
Primates in several zoos have become infected. Several gorillas at the zoo in Atlanta tested positive last week.
To protect them from Covid, animals at the Washington zoo will be injected with a product developed by Zoetis, a drug company that makes vaccines and medicine for pets and livestock.