(CNN) Animal keepers at the Smithsonian's National Zoo in Washington, DC, are keeping a close eye on their lions and tigers after the big cats tested presumptive positive for Covid-19.
Six African lions, a Sumatran tiger and two Amur tigers are being treated with anti-inflammatories and anti-nausea medication to help with their discomfort and loss of appetite, the zoo announced in a news release. They're also getting antibiotics to treat presumptive secondary bacterial pneumonia.
Several of the lions and tigers displayed symptoms last weekend, including decreased appetites, coughing, sneezing and lethargy, the release said.
Fecal samples from the lions and tigers were tested and came back with presumptive positive results. Final results are expected in the next few days, the zoo said.
The zoo will remain open and the lions and tigers will be able to go outside in their outdoor habitats.
"Given the substantial distance between the animals and visitors, the public is not at risk," the statement said.
The zoo said no other animals have shown signs of infection.
"The Zoo has conducted a thorough investigation of all staff that were in close proximity to the lions and tigers. There is no evidence to pinpoint the source of the infection," the statement said. "While it is possible the infection was transmitted by an asymptomatic carrier, it has been standard practice for all animal care staff and essential staff to mask indoors in all public and non-public areas."
Sumatran tigers are listed as critically endangered, with a population of less than 400, according to the World Wildlife Fund. Amur tigers are classified as endangered and African lions are vulnerable on the IUCN Red list.
Last week, a group of lowland gorillas at Zoo Atlanta tested positive for Covid-19, according to zoo officials. Only two of the 20 gorillas are still symptomatic, the zoo said in a statement Friday.
The US Department of Agriculture has authorized a SARS-CoV-2 vaccine for zoo animals, and the National Zoo said it would administer it to susceptible animals once it becomes available.
Zoo Atlanta says it has vaccinated its orangutans, lions, tigers, and clouded leopard.