Coronavirus: Bronx Zoo tiger tests positive for COVID-19

Malayan tiger 'Nadia' believed to be infected by a zoo employee in the first known animal case of COVID-19 in the US.

Nadia underwent X-rays, an ultrasound and blood tests to try to figure out what was ailing her.

A tiger at New York's Bronx Zoo has tested positive for the new coronavirus, in what is believed to be the first known infection in an animal in the United States or a tiger anywhere in the world, federal officials and the zoo said. 

The four-year-old Malayan tiger named Nadia was among a group of six other animals to have also fallen ill, the Wildlife Conservation Society, which manages the zoo, said in a statement on Sunday. 
She was screened for the COVID-19 disease after developing a dry cough along with three other tigers and three lions, it said, adding that all of the cats are expected to recover. 

The test result stunned zoo officials: "I couldn't believe it," director Jim Breheny said.

The coronavirus 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 news agency. Calle said they did not know which employee infected the tiger.

"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."

Transmission in animals

The first tiger at the zoo, which has been shut since mid-March, began showing signs of illness on March 27, according to the US Department of Agriculture, which performed the test at its veterinary lab.

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 epicentre of the outbreak in the US.

While other tigers and lions were also exhibiting symptoms, 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 anaesthesia, Calle said.

"The tigers and lions weren't terribly sick," he said.

You cannot send human samples to the veterinary laboratory, and you cannot send animal tests to the human laboratories, so there is no competition for testing between these very different situations."

— Bronx Zoo (@BronxZoo)April 6, 2020

The finding raises new questions about the transmission of the virus in animals.

The US Department of Agriculture said there are no known cases of the virus in US pets or livestock.

“There doesn’t appear to be, at this time, any evidence that suggests that the animals can spread the virus to people or that they can be a source of the infection in the United States," Jane Rooney, a veterinarian and a USDA official, said in an interview.

The coronavirus outbreaks around the world are driven by person-to-person transmission, experts say.

There have been a handful of reports outside the US of pet dogs or cats becoming infected after close contact with contagious people, including a Hong Kong dog that tested positive for a low level of the pathogen in February and early March.