It started with a cough. One day in September 2021, 25-year-old Amanda, the matriarch tiger of Carole Baskin’s Big Cat Rescue, was basking in the Florida sun. The next, she just wasn’t herself. She developed a peculiar dry hack, lost her appetite, and was hiding in the shadows.
Over the next few days, she had trouble breathing. Concerned caretakers corralled the 260-pound tiger to draw blood for tests: Could it be COVID? Their facility wasn’t set up for that kind of diagnosis, so someone suggested getting a rapid COVID test from a local pharmacy. That home test came out positive, and there was a lot of talk about Amanda’s age; the average lifespan of a tiger in captivity is 22 years.
“She might have been the oldest tiger in the world,” said Baskin, CEO of Big Cat Rescue, where Amanda lived for the previous 10 years. Baskin and her sanctuary, which is located near Tampa, rose to fame at the start of the pandemic when she was featured on Netflix’s Tiger King.
The series turned Baskin into a pop culture icon and a star of internet memes. Some idolize her as a paragon of animal activism who fights against inhumane roadside zoos. Others believe she is an intense cat lady and theorize about her role in the disappearance of her millionaire husband.
What’s clear is that Baskin is definitely a real fan of the felines. She makes her way around Big Cat Rescue’s 67 acres in a golf cart hand-painted by her daughter in purple-and-pink leopard spots.
One October afternoon, Baskin coasted down the asphalt pathway, surrounded by tropical foliage, pausing her golf cart at each immaculately maintained enclosure to speak in baby talk to the animals. “Aren’t you chatty today?” she said to a Savannah cat, a hybrid between a serval and domestic cat who tends to meow a lot.
She never once took off her mask, which was printed with a cartoon tiger’s mouth licking its lips. She wasn’t taking any chances.
However, it’s not that surprising that Baskin’s tiger tested positive for COVID; it's been a common problem in zoos and sanctuaries throughout the pandemic. This is unsettling news for animal welfare, but there could be even more distressing implications for public health. When there is an animal outbreak of SARS-CoV-2, the virus can mutate and even spread back to humans. Worst-case scenario, a new variant will form that is extra contagious or causes more severe illness. Such concerns have given rise to the development of special veterinary vaccines specifically to prevent COVID in animals.
Zoo animals across the US have gotten COVID
The first known COVID outbreak in zoo animals was at New York’s Bronx Zoo in April 2020. First a tiger was infected, followed by seven other big cats. Then eight of the nine gorillas at the San Diego Zoo became sick with COVID in January 2021.
In September 2021, all the lions and tigers at the Smithsonian’s National Zoo in Washington, DC, had the virus. Things got even worse at a zoo in Sioux Falls, South Dakota, where a 2-year-old snow leopard died from COVID-related complications in October. In November, three more snow leopards died from COVID at a zoo in Lincoln, Nebraska. And yet another snow leopard died of COVID complications in Bloomington, Illinois, in January 2022.
Similar reports have rolled in from veterinarians, zoos, animal sanctuaries, and wildlife experts all over the world. The virus has also infected otters, hyenas, deer, hippos, and even dogs and cats.
Much is known about zoonosis, the transfer of infections from animals to humans. However, we know less about zooanthroponosis, the transfer of infectious organisms from humans to animals. That lab test is happening all around us in real time.
One scientist looking into zooanthroponosis is Arinjay Banerjee, a virologist at the University of Saskatchewan.
“I can't actually give you examples of how many viruses have gone from humans into animals,” Banerjee said. “That's how little it's studied.”
Recent studies have suggested that SARS-CoV-2 originated in horseshoe bats and may have spread from animals to humans at the Huanan Seafood Market in Wuhan, China (although that’s still being debated). Bats can’t easily spread viruses directly to humans, so COVID may have made the jump via an intermediary species, sometimes referred to as a “mixing vessel.”
Banerjee said there has been such limited research on zooanthroponosis because there has never been a perceived threat in terms of human life or economics.
But that might be changing.
There have been COVID outbreaks around the world at mink farms, including at least 18 in the United States. According to a 2020 study in the journal Science, 68% of the workers at 16 mink farms in the southeastern Netherlands either had COVID or were infected in the past (most likely from other humans) in June 2020. Outbreaks, like one in the Netherlands, can produce a variant in animals that then spreads back to humans. In at least some of the cases, the farmworkers did contract a variant virus from infected minks. Thankfully, the strain in the Netherlands was only different, neither more infectious nor vaccine-resistant.
“We got lucky with that one,” Banerjee said. “The mutation was not of consequence.”
Since the start of the pandemic, COVID has served as a reminder of our connection to animals. However, the information is in constant flux. A lot of what we are learning is happening by accident.
“The wet markets have done the experiments for us, testing which animals can actually be infected by these viruses,” said Paula Cannon, a distinguished professor of molecular microbiology and immunology at the University of Southern California’s Keck School of Medicine. “Now, as humans are interacting with animals in our zoos and sanctuaries, we’re doing another experiment.”
COVID cases at Big Cat Rescue
Amanda the tiger was, unfortunately, part of that experiment, the culmination of a very tough life, all of which she spent in captivity.
Born in 1996 at a roadside zoo in New Jersey, Amanda and her two brothers, Arthur and Andre, were heavily drugged almost every day so tourists could take photos with them. This type of “pay-to-play” operation is something many animal activists seek to eradicate, including Baskin. The USDA ordered the New Jersey facility to close after one of its other tigers got loose; Amanda and her brothers eventually found their way to Big Cat Rescue in 2011.
Amanda started showing signs of illness when she was on “vacation.” Every month at Big Cat Rescue, one of the larger animals is given exclusive access to a massive 2.5-acre lakefront vacation enclosure. For comparison, Florida law requires a minimum cage size of just 240 square feet for up to two tigers. The smallest enclosure at Big Cat Rescue is 1,200 square feet, and that’s for a Savannah cat of just 20 pounds.
Before Amanda got sick, volunteers saw her leaping up onto wooden observation decks in the vacation enclosure, eschewing the ramps available for older animals. Her appetite was strong too. She was enjoying treats like “blood popsicles,” which are made from runoff of the hundreds of pounds of meat required to feed the animals at Big Cat Rescue each day.
Just a few days later, Amanda was dying. The Big Cat Rescue caretakers gathered inside the enclosure, standing over her as she lay tranquilized on a blanket. Her blood work had come back from the lab. Page after page, line after line, it showed her organs were failing. They had no choice; Amanda was euthanized on Sept. 16, 2021.
Amanda did not die from COVID, Baskin said, but the virus may have exacerbated conditions with which she was already grappling. Further, Baskin said she wasn’t convinced that Amanda even had the virus. Believing the home test they used might be a false positive (the false positive rate of these tests is often less than 1% in humans), caretakers took a sample from Amanda to send to a laboratory.
While awaiting results, Baskin’s team noticed that another tiger, Aria, who lives in the enclosure adjacent to Amanda’s, also just wasn’t herself. This time around, they didn’t skip a beat. They collected a sample from Aria, sent it off to the lab, and monitored her symptoms closely.
When Amanda’s test result came back, it confirmed that she had COVID at the time of her death. A few days later, Aria’s result came back; hers was also positive, but she recovered.
A COVID vaccine for animals
The good news is that there is an option to help stop the spread of viruses from humans to animals (and back again): routine vaccinations for both.
There are several veterinary vaccines for COVID-19 in different phases of development, including from Applied DNA Sciences and Evvivax. One from Russian company Carnivac-Cov has been in circulation since May 2021. But the company that has made the most traction and been the most visible is Zoetis, which bills itself as “the largest global animal health company.”
Zoetis started working on the formulation as early as March 2020, just after news broke that a Pomeranian in Hong Kong tested positive for COVID. “That was our initial reason, because ultimately, cats and dogs are our bread and butter,” said Christina Lood, the company’s communications director.
At the time, the Hong Kong government was also requiring quarantines for pets of COVID-positive owners. But that was early in the pandemic when much less was known. Now, we have learned that even though pets can get COVID, the risk of them spreading the SARS-CoV-2 virus to people is low, according to the CDC.
“They’re really not playing an active role in spreading the disease to humans,” Lood said. “The best way to protect your pets from COVID is to get yourself vaccinated.”
While no veterinary COVID vaccine has been fully approved for use in animals, the Zoetis shot is already being administered all over the world.
First up was the gorilla troop at the San Diego Zoo. After the January 2021 outbreak, the zoo’s animal care team asked Zoetis for help. The company had a few spare vials left over from testing and sent them to the zoo in March after receiving special authorization from the USDA. Because the gorillas received COVID vaccines before almost all American humans, there was a burst of international news coverage.
Then came widespread interest from over 70 zoos and sanctuaries throughout the US. Zoetis responded with an initial donation of over 11,000 free doses to the zoos. The company has since expanded that program to offer over 26,000 shots to facilities worldwide, including one in Chile and six in Canada.
Not Baskin’s, though. She and the veterinary team at Big Cat Rescue ran a risk analysis and decided not to vaccinate their animals yet. A big part of this decision: Big Cat Rescue is currently closed to outside visitors.
The only people who enter the property are Baskin, her family, and her team of 70 volunteer workers. Everyone on the animal care team is vaccinated, and they all wear masks when they’re near the cats or preparing their food.
The Big Cat Rescue team members are also concerned about their older animals’ ability to endure the turmoil of vaccination. About half of their tigers, lions, leopards, and ligers (a genetic hybrid of a lion and a tiger) are over the age of 12; seven are over 20. Baskin described the process of giving injections as traumatic for the animals.
“We have to vaccinate for rabies and regular cat issues every three years, and that’s a rodeo none of us look forward to,” she said.
Handlers have to guide the animals through tunnels into small lockout boxes; they lower a special device called a “catacomb,” which presses the animal to the side of the cage.
“The whole time, they’re flailing around trying to get out of there,” Baskin said, adding that she worries they could even have a heart attack.
The North Carolina Zoo vaccinates animals with a method that involves treats. Located 70 miles west of Raleigh, the world’s largest natural habitat zoo was one of the facilities approved by the USDA to administer the Zoetis shots. Between Oct. 18 and 20, caretakers vaccinated 33 animals, including 16 chimpanzees, seven western lowland gorillas, four hamadryas baboons, two African lions, two North American mountain lions, and a sand cat. They used positive reinforcement to vaccinate, gradually training the animals to present their hind end in exchange for edible bribes.
The first animal vaccinated at the North Carolina Zoo was Olympia, a 23-year-old gorilla who keeper Stephanie Tien says is very cautious.
“She’s very suspicious of everything. We kind of joke around that she’s the conspiracy theorist of the gorilla troop,” Tien said.
Tien and her colleagues thought if Olympia sensed something was going on that she might not cooperate for the injection. So, they started with her. Afterward, Tien showered Olympia with gifts: peppermint, jelly, fruits, and a little bit of a protein bar.
How long the protection lasts is not yet known. All the animals received a second shot about three weeks after their first, but whether they will require subsequent boosters is still to be determined. Jb Minter, the zoo’s director of animal health, has been collecting blood samples to test the animals’ immunity levels.
“I have chimps and a lion and a mountain lion that will voluntarily give blood,” he said.
Minter planned to test them all at once as a cost-saving measure. But just recently, the USDA contacted him with an offer to test them at a discount. Data will be aggregated from all of the zoos that choose to participate, which could play a role in understanding the vaccine’s efficacy in different species.
“It was great on our part when the USDA reached out to us,” he said. “The more information we can gather and dispense out to zoos and institutions that are holding these exotic animals, the better the situation for their health.”
The North Carolina Zoo, a facility that has seen zero positive cases, is being proactive.
“We have been very lucky,” Minter said, knocking a couple of times on his wooden desk.
Minter works from both the zoo’s on-site hospital and the exhibits of more than 200 species. His daily uniform consists of a blue polo shirt embroidered with the zoo’s logo and a wooden bead choker around his neck.
Many zoo regulars recognize Minter on sight. At the chimpanzee exhibit, a young boy ran up to give him a hug. The animals recognize him too. Minter called for Jon, an older chimp who was peering at him from atop a towering tree trunk. Jon heard him and ambled down to say hello through the glass.
As for Big Cat Rescue, no other animals other than Aria and Amanda have had positive tests. Baskin said she and her lead veterinarian may decide to vaccinate each of the cats when it comes time for their three-year shots.
“I think that would be his option,” she said. “We haven’t discussed it, but we also haven’t had anybody due for their vaccines yet.”
That afternoon, a pair of smiling volunteers were making the rounds with medicines, catnip, and blood popsicles, of course. Another group had just finished constructing ornate piñatas for the cats to destroy on an internet livestream later that week. Baskin was supervising from her golf cart.
Continuing her tour, she stopped in front of Aria’s enclosure.
“Aria, baby!” Baskin said before moving on.
She got to Amanda’s enclosure. She slowed the cart a bit to talk about how they had removed part of the fence to give Aria more space. But there was no reason for her to stop.