The first known infection in an animal in the U.S. Other tigers and lions have become sick. Nadia, the 4-year-old Malayan tiger that tested positive, was screened for the COVID-19 disease after developing a dry cough along with three other tigers and three lions, the Wildlife Conservation Society, which manages the zoo, said in a statement. All of the cats are expected to recover, it said. The virus that causes COVID-19 is believed to have spread from animals to humans, and a handful of animals have tested positive in Hong Kong. But officials believe this is a unique case because Nadia became sick after exposure to an asymptomatic zoo employee, Paul Calle, chief veterinarian at the Bronx Zoo, told Reuters. Calle said they did not know which employee infected the tiger.