Something was wrong with a tiger in central India’s Pench Tiger Reserve earlier this month. For several days, wildlife managers had observed the 10-year-old male making frequent visits to a nearby pond, possibly, they speculated, because it was running a high fever. Though staff administered antibiotics, the tiger didn’t improve and eventually died by the water hole. A mysterious respiratory illness was at first the suspected cause of death.
Two days later — before authorities determined that an impacted intestine arising from a giant hairball had likely killed the cat — Indian officials put the country’s 50 wild tiger reserves on high alert. The country is home to 2,967 wild tigers, roughly three-quarters of the world’s total remaining non-captive population. And the cats are known to suffer from respiratory ailments, such as rhinotracheitis. But the announcement that a captive 4-year-old tiger at New York’s Bronx Zoo had tested positive for the coronavirus — the first confirmed case of the virus in a big cat — intensified concerns.
“This coronavirus could turn out to be very dangerous,” said Anup Kumar Nayak of the National Tiger Conservation Authority, the government agency charged with protecting India’s big cats. “We do not know what will happen in the future, but we are taking every precautionary measure. We have to take care of them.”
Dr. Nayak’s agency and India’s Ministry of Environment, Forests and Climate Change have advised wildlife wardens in all states with tigers to restrict the movement of people into national parks, sanctuaries and reserves. Tigers must also be observed for respiratory symptoms, such as nasal discharge, coughing or labored breathing, the authority said. Personnel relocating tigers that have been in conflict with people or handling sick cats would also need to be tested for the virus before any interactions with the animals.
At the time of the Pench tiger’s death, the agency had not established a protocol for coronavirus testing. Moving forward, veterinarians conducting post-mortem investigations will be required to collect and send samples to national laboratories.
In the two weeks since the advisories were issued, Dr. Nayak said wildlife wardens have not reported behavioral changes in tigers that would indicate any had become infected. But they continue to look out for more sick tigers.
India entered a nationwide lockdown on March 24, but many wildlife workers have remained on the job. At Kanha Tiger Reserve in the central state of Madhya Pradesh, hundreds of rangers patrol the 362-square-mile area to protect the 90 endangered tigers estimated to live there.
“In Kanha, we have our own vets and veterinary hospital, so we are well prepared,” said L. Krishnamoorthy, field director of the reserve. “It’s a concern everywhere, but we are very watchful.”
In a series of lab experiments at China’s Harbin Veterinary Research Institute, researchers demonstrated that the virus reproduces “efficiently” in domestic cats and can be transmitted by respiratory droplets between animals. The results were uploaded last month to a preprint website, and have not yet been subject to peer review.
Scientists aren’t yet sure how the coronavirus could affect big cats in the wild. A controlled or modified setting, such as a lab or a zoo, doesn’t offer an accurate model for how species interact in an ecosystem. Chris Walzer, executive director of health at the Wildlife Conservation Society in New York, suggested that the virus may have spread to Nadia, the Bronx Zoo Malayan tiger, through pressure-washing of cages that vaporized the virus. Still, she only expressed mild symptoms — a cough and decreased appetite — as did six other big cats at the zoo.
Tigers are known to be vulnerable to rabies, anthrax and canine distemper, an often fatal morbillivirus commonly spread by stray dogs. The cats can also fall victim to feline infectious peritonitis, a disease caused by another coronavirus strain that affects the gastrointestinal tract.
India is likely exhibiting an overabundance of caution because of the fragile status of tigers in the country. And some critics say authorities are focusing on the wrong problem.
Ullas Karanth, the director of the Center for Wildlife Studies in India, thinks fears over the virus are misdirected. Illegal hunting of the tiger’s prey species for meat by desperate locals during the lockdown is a bigger threat to wild tigers than the disease itself, he says. Seven poachers were recently arrested in Bandipur Tiger Reserve with dead deer. “There is a real surge in this kind of hunting,” Dr. Karanth said.
Other conservationists warn that because of the restrictions, impoverished people living near and in protected areas will be unable to collect subsistence products, like firewood and food. In a letter to the environment ministry, Ravi Chellam, an Indian wildlife biologist, and others urged officials not to restrict or evict villagers from protected areas.
“Indian wildlife faces far greater threats from habitat fragmentation, degradation, destruction, climate change, poaching and potentially many other diseases than from Covid-19,” Dr. Chellam said.
