A four-year-old female Malayan tiger at the Bronx Zoo has tested positive for the coronavirus.
The Bronx Zoo, in New York City, says the test result was confirmed by the National Veterinary Services Laboratory in Iowa.
Nadia, her sister Azul, as well as two Amur tigers and three African lions, had developed a dry cough and all are expected to fully recover, it says.
The cats are believed to have been infected by a zoo keeper.
"We tested the cat [Nadia] out of an abundance of caution and will ensure any knowledge we gain about Covid-19 will contribute to the world's continuing understanding of this novel coronavirus," the zoo said in a statement on Sunday.
The big cats did have some decrease in appetite but "are otherwise doing well under veterinary care and are bright, alert, and interactive with their keepers".
The zoo said it is not known how the virus will develop in animals like tigers and lions since various species can react differently to new infections, but all the animals will be closely monitored.
None of the zoo's other big cats - four other tigers, snow leopards, cheetahs, a clouded leopard, an Amur leopard, a puma and a serval - are showing any signs of illness.
"Our cats were infected by a person caring for them who was asymptomatically infected with the virus or before that person developed symptoms," said the zoo.
All the tigers showing symptoms were housed in the zoo's Tiger Mountain area.