The Smithsonian's National Zoo in Washington, D.C. announced six African lions, a Sumatran tiger, and two Amur tigers tested presumptive positive for the virus that causes COVID-19.

The animals' symptoms included decreased appetites, coughing, sneezing, and lethargy, the zoo said.

The zoo still doesn't know how the animals contracted the virus.

"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," the zoo said in a statement.

The animals are being treated with various drugs including antibiotics, anti-inflammatories, and anti-nausea medication.