A tiger at New York City's Bronx Zoo has ­tested positive for COVID-19, the institution said Sunday, and is believed to have contracted the virus from a 

caretaker who was asymptomatic at the time.

The 4-year-old Malayan tiger named Nadia along with her sister Azul, two Amur tigers and three African lions all developed dry coughs and are expected to fully recover, the Wildlife Conservation Society that runs the city's zoos said in a statement.

The zoo decided to test only Nadia because she was the sickest and had started to lose her appetite, and they did not want to subject all the cats to anesthesia, the zoo's chief veterinarian Paul Calle said.

Nadia underwent X-rays, an ultrasound and blood tests to try to figure out what was ailing her. They decided to test for COVID-19 given the surge in cases in New York City, the epicenter of the outbreak in the US.

"This is the first time that any of us know of anywhere in the world that a person infected the animal and the animal got sick," Calle said, adding that they planned to share the findings with other zoos and institutions. "Hopefully we will all have a better understanding as a result."

All four of the zoos and the aquarium in New York City have been closed since March 16.

The zoo emphasized that there is "no evidence that any person has been infected with COVID-19 in the US by animals, including by pet dogs or cats."

According to the US Department of Agriculture website, there had "not been reports of pets or other animals" in the US falling ill with coronavirus prior to news of the tiger Nadia.

"It is still recommended that people sick with COVID-19 limit contact with animals until more information is known about the virus," the department's website says. 

In late March a pet cat was discovered infected with the novel coronavirus in Belgium, following similar cases in Hong Kong where two dogs tested positive for COVID-19.

All of those animals are believed to have contracted the virus from the ­people they live with.