A Tiger in the Bronx Zoo Tested Positive for COVID-19

Nadia, a four-year-old Malayan tiger, is the first known animal to test positive for coronavirus in the United States

Nadia and her sister Azul as cubs at the Bronx Zoo.
Nadia and her sister Azul as cubs at the Bronx Zoo in 2016. Both tigers showed symptoms of COVID-19, and Nadia tested positive for the virus. Credit: Julie Larsen Maher © WCS

A four-year-old Malayan tiger at the Bronx Zoo in New York City has tested positive for coronavirus—the first-known animal in the United States to test positive for the virus.

Zoo officials tested the tiger, named Nadia, out of an abundance of caution after she started showing symptoms on March 27. She appeared to have a dry cough and a mild loss of appetite, but she is expected to make a full recovery. The Wildlife Conservation Society (WCS), which runs the Bronx Zoo, announced Sunday that Nadia’s sister Azul, two Amur tigers and three African lions had also developed similar symptoms.

“Though they have experienced some decrease in appetite, the cats at the Bronx Zoo are otherwise doing well under veterinary care and are bright, alert, and interactive with their keepers,” notes the WCS in a statement.

In a statement posted to the Bronx Zoo’s Twitter, chief veterinarian Paul Calle explained that animals require different testing methods than humans and that Nadia’s test was processed in a veterinary laboratory, and therefore did not take resources away from human patients. Testing big cats requires general anesthesia, which poses certain health risks to the animals. Because the other big cats had the same symptoms, the zoo only tested one cat for the virus, the United States Department of Agriculture (USDA) said in a statement.

Officials suspect that the tiger contracted the virus from a human handler, which makes this case a rare example of human-to-animal transmission. The Bronx Zoo closed to the public on March 16 but still requires about 300 essential employees from its 700-person staff to come in each day to care for the zoo’s roughly 6,000 animals, Julia Jacobs reported last week for the Times.

“That’s the assumption, that one of the keepers who was asymptomatic or shedding the virus before they were sick was the source of the infection,” Calle tells Joseph Goldstein of the New York Times. He says that while handlers keep a barrier between themselves and the big cats, they will generally stand within a few feet of the animals to feed them.

Nadia and her sister Azul were born in January 2016 and debuted at the Bronx Zoo later that year. The sisters were the third litter of Malayan cubs born at the Zoo and live in the zoo’s “Tiger Mountain” exhibit. With less than 200 of the species left in the wild, International Union for the Conservation of Nature (IUCN) lists Malayan tigers as “critically endangered.”

Video: Nadia and Azul playing in the Tiger Mountain enclosure, 2016 debut at Bronx Zoo https://www.youtube.com/watch?v=QTHY0qbWDfs&feature=emb_title

The ramifications of Nadia’s diagnosis are unknown. Captive tigers in the United States outnumber those in the wild and are often prone to abuse in roadside zoos, Sharon Guynup reports for National Geographic. The plight of some captive tigers became recently well-publicized, thanks to the Netflix docuseries Tiger King. Dan Ashe, president of the American Association of Zoos and Aquariums, tells National Geographic’s Natasha Daly that he fears tigers at substandard zoos might not receive adequate treatment were they to become infected with COVID-19.

“Anybody who has watched Tiger King, you think a facility like that would be able to respond in an appropriate way to information like this?” he told National Geographic.

Nadia’s diagnosis also raises questions about the susceptibility of other animals to COVID-19, including household pets. Meagan Flynn for the Washington Post reports that one cat and two dogs tested positive for COVID-19 in Hong Kong, and a cat in Belgium exhibited symptoms consistent with coronavirus after its owner tested positive.

In late January this year, the National Zoo developed a response plan for COVID-19. The Zoo continually, monitors and potentially amends their response as new information becomes available. Since early March, essential staff has practiced social distancing when working together and while working with certain animals, like primates, that are known to be susceptible to contracting illnesses from humans.

In response to the Centers for Disease Control and Protection’s updated recommendation about masks, essential zoo staff were directed to wear masks or washable face coverings when working within six feet of each other as well as with animals of increased concern and their feeding and enrichment equipment. After the announcement about the tiger’s positive COVID-19 diagnosis at the Bronx Zoo, the National Zoo expanded their list of animals of increased concern, which includes: primates; felids, including tigers, lions, cheetahs, clouded leopards and others; mustelids, including otters, skunks and ferrets; and herpestids and viverrids, like meerkats, mongooses, binturong, and civets.

In light of limited evidence about how coronavirus affects animals—domesticated or not—the USDA recommends that “people sick with COVID-19 limit contact with animals until more information is known about the virus.”

“If a sick person must care for a pet or be around animals, they should wash their hands before and after the interaction,” the agency said in a statement.

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