A 4-year-old tiger at the Bronx Zoo tested positive for COVID-19 on April 5, the diagnosis confirmed thanks in part to an assist from Cornell’s Animal Health Diagnostic Center (AHDC).

The female tiger, Nadia, along with six of the zoo’s other big cats developed signs of respiratory disease, including a dry cough, in late March. Nadia’s caretakers sent respiratory swabs and tracheal wash samples to Cornell and to the University of Illinois College of Veterinary Medicine Diagnostic Lab.

The AHDC, housed at the Cornell College of Veterinary Medicine, has experts who run hundreds of thousands of diagnostic tests annually for the state and others.

“As the veterinary diagnostic lab of the New York State Department of Agriculture and Markets, we work in tandem with the state veterinarian and public health experts to run tests that inform both animal and human health measures,” said Dr. François Elvinger, executive director of the AHDC. “Early in the COVID-19 outbreak, we prepared to conduct animal testing for SARS-CoV-2, should it be requested by the state veterinarian.”

Diagnostic experts at the AHDC applied polymerase chain reaction and sequencing tests – adapted for use in animal samples, with animal-specific reagents – and performed microscopic examination of the samples. The procedure is similar to the CDC test used in humans, but AHDC personnel were careful to not use reagents needed by human clinical laboratories.

The test showed Nadia might have been infected with SARS-CoV-2, the coronavirus that causes COVID-19. Further sequencing confirmed the results; official confirmation of the diagnosis was performed April 5 at the United States Department of Agriculture’s National Veterinary Services Laboratories in Ames, Iowa.

The American Veterinary Medical Association and the Centers for Disease Control and Prevention both report there is no reason to think that domestic animals, including pets, can spread COVID-19 to people or that they might be a source of infection in the United States.

The Wildlife Conservation Society has implemented additional preventive measures at their zoos for staff and resident animals. Nadia and the other big cats are all expected to fully recover; none of the zoo’s other exotic cats has shown signs of illness.

Melanie Greaver Cordova is managing editor at the College of Veterinary Medicine.