Four more tigers and three lions at the Bronx Zoo in New York City have tested positive for the virus that causes COVID-19, the zoo announced Wednesday afternoon, following a National Geographic inquiry. This comes nearly three weeks after one tiger at the zoo was confirmed to have the virus and six other cats were said to be exhibiting symptoms.
The diagnosis of the tiger, named Nadia, represented “the first time, to our knowledge, that a [wild] animal has gotten sick from COVID-19 from a person,” Paul Calle, chief veterinarian for the Bronx Zoo, said April 5. The big cats likely contracted the coronavirus from an infected but asymptomatic zookeeper whose identity is unknown, Calle says: “It’s the only thing that makes sense.” Calle says.
The zoo has been closed to visitors since March 16. Initially it did not plan to test the other cats showing symptoms, because doing so would require sedation, which can be dangerous. But the U.S. Department of Agriculture subsequently updated an online database with information that a lion in New York had also been confirmed as testing positive for the virus on April 15. National Geographic contacted the Bronx Zoo seeking more information on April 22. And shortly thereafter the Wildlife Conservation Society, the nonprofit that runs the Bronx Zoo, issued a press release announcing that four additional tigers and three lions had tested positive. The zoo confirmed in the press release that the additional tests were done using fecal samples and did not require sedation.
It is not clear when the additional tests on the three lions and four tigers were conducted or when the zoo received the results; a zoo spokesperson did not respond to questions about the timing. The USDA did not respond to National Geographic’s request for comment by press time.
Cats, both wild and domestic, are susceptible to feline coronavirus, but until recently, it was unknown whether they could contract SARS-CoV-2. A new Chinese study has found that cats may be able to infect each other, and scientists are rushing to learn what other species may be able to be infected by it.
After developing a dry cough in late March, the four-year-old Malayan tiger, Nadia, was tested for the virus on April 2, according to Calle. Nadia’s sister, two Siberian tigers, and three African lions have also had coughs and a loss of appetite, though they have not been tested. The zoo has the seven cats under veterinary care and expects them to recover, Calle says, though the Wildlife Conservation Society, the nonprofit that runs the Bronx Zoo, cautioned in a news release that it’s unknown how the disease might progress in animals.
When Nadia started showing symptoms, the veterinary team did a number of diagnostic tests and blood work. “Considering what’s going on in New York City, we of course did the COVID testing,” Calle says. The team took samples at the zoo, after sedating Nadia. They sent the samples for testing to the New York State Diagnostic Laboratory at Cornell University and to the University of Illinois College of Veterinary Medicine Veterinary Diagnostic Laboratory. It is not the same type of test that health care providers give to people, says Calle, “so there is no competition for testing between these very different situations.”
According to the USDA and the Centers for Disease Control and Prevention, there is currently no evidence that domestic or captive wild animals can spread the novel coronavirus to people. (It’s believed the virus infecting humans likely developed from a very closely related coronavirus found in bats.)
This is all completely new, Calle says, so there are many unanswered questions, including whether tigers and lions are more susceptible to coronavirus than other animals. None of the zoo’s other big cats, including snow leopards, cheetahs, a clouded leopard, an Amur leopard, and a puma are showing symptoms.
Zookeepers around the country have been making extra efforts to protect great apes in their care, as great apes can easily catch respiratory illnesses from humans. Experts have warned that they may be particularly susceptible to coronavirus.
The Bronx Zoo team has shared the diagnostic information widely with the zoo and scientific community, Calle says. “I suspect that there are other cases, and now that we’re sharing this information i have a hunch other likely cases will turn up.”
Dan Ashe, president of the American Association of Zoos and Aquariums (AZA), which accredits more than 200 zoos in the U.S., including the Bronx Zoo, commends Calle’s team for their quick action. He says that the AZA has helped distribute information from the USDA, which cautions about the potential transfer from humans to felids, and from the Bronx Zoo, about increased safety measures, including wearing masks and goggles to protect animals and keeping a distance of six feet whenever possible.
Ashe says he believes the priority should be testing people. “If we’d known the keeper had COVID-19 they wouldn’t have been at work,” he says. “If [the virus] can go from people to big cats, the most important thing we can do is test the people.”
Although Ashe says he’s confident that accredited AZA facilities will continue to be proactive, he’s concerned for the big cats at the many substandard roadside zoos around the U.S. “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 says that the majority don’t have veterinarians on staff, and it’s unlikely tests would be done. The cub-petting and close contact offered by these facilities “is troublesome in best of circumstances,” he says, let alone at a time when the CDC and USDA are recommending maintaining distance among humans, and between humans and cats.
John Goodrich, chief scientist and tiger program director at Panthera, a global big cat conservation organisation, is concerned for wild tiger populations. “Big cats like tigers and lions are already facing a litany of threats to their survival in the wild. If COVID-19 jumps to wild big cat populations and becomes a significant cause of mortality, the virus could develop into a very serious concern for the future of these species.”
India, too, has followed the American suit as the Central Zoo Authority (CZA) on Monday put all zoos, wildlife sanctuaries, national parks and tiger reserves across the country on “highest” alert. In a letter to all states and Union territories, CZA Member Secretary S P Yadav said, “reduce the human wildlife interface and restrict the movement of people to national park, sanctuaries and tiger reserves.”
Animals will be closely monitored on CCTV. Samples shall be collected fortnightly in suspected cases, which can then be sent to the National Institute of High Security Animal Disease in Bhopal, the National Research Centre on Equines in Haryana’s Hisar and the Indian Veterinary Research Institute in Bareilly, Uttar Pradesh, the letter stated.
“Sick animals should be isolated and quarantined,” it added. Adhering to the guidelines, no keeper or handler should be allowed in the vicinity of animals without safety gear, preferably personal protective equipment (PPE). They should have least contact with animals while providing them feed, it said.
Additional reporting by Pooja Naik. This story has been updated on April 23, 2020.