Lions, tigers and house cats, oh my.
Seven tigers and lions at the Bronx Zoo in New York developed dry coughs and other symptoms of coronavirus after being exposed to a zookeeper “asymptomatically infected with the virus,” according to a press release from the zoo on Sunday.
This follows a report that a Belgian woman with Covid-19, the disease caused by the novel coronavirus, infected her pet cat in early March. But even though the cat had respiratory problems and high levels of the virus in its vomit and feces, researchers aren’t yet sure if the cat was sick from Covid-19 or another illness.
So what do these cases mean for felines and their human caretakers? It appears that while humans can pass the coronavirus on to cats, experts agree that getting coronavirus from a cat is extremely unlikely.
“The bottom line is that there is no evidence that any cat, large or small, can transmit the virus back to humans,” said veterinarian Dr. Sarah Caddy, a clinical research fellow at the University of Cambridge.
But until we know more about coronavirus, experts are also suggesting anyone diagnosed with Covid-19 avoid contact with their cats, to avoid the extremely rare chance that you might infect your pet.
“If a member of the household becomes sick with Covid-19, they should be isolated from all members of the household, pets included,” said professor Jacqui Norris, from the Sydney School of Veterinary Science at The University of Sydney.
Nadia, a 4-year-old female Malayan tiger, was anesthetised and tested for Covid-19 “out of an abundance of caution” and was found to be positive, the Bronx Zoo announced Sunday. Her sister Azul; two Amur tigers; and three African lions also lost appetite and developed a dry cough, but “are bright, alert and interactive with their keepers,” the zoo said.
However, other tigers, lions, snow leopards, cheetahs, clouded leopards, Amur leopards, pumas or servals the infected zookeeper cared for are showing no signs of the disease.
Experts say it’s not surprising that exotic cats can develop Covid-19, also called SARS-CoV-2.
Dr. John Williams, chief of the division of pediatric infectious diseases at the University of Pittsburgh Medical Center Children’s Hospital of Pittsburgh, has studied coronviruses for decades. He said that tigers also caught SARS-CoV, the related coronavirus that causes severe acute respiratory syndrome (SARS), during the outbreak from 2002 to 2004.
However, it is surprising that the Bronx tiger became infected with “what must have been a fairly low dose of virus – we can assume the tiger did not have continual close contact with the asymptomatic zoo keeper,” said Caddy.
“It is possible that tigers in captivity are more susceptible to the virus than household moggies as there is a 5% difference between their genomes,” she said. (Moggie is an affectionate British slang word for non-pedigree cats.)
An unpublished study in China, released without peer review last week, also found domestic house cats can be infected with SARS-CoV-2 if large doses of virus are administered via their nostrils in an experimental setting.
“These researchers squirted the virus down the cats noses in high concentration, which is pretty artificial,” Williams said.
The fact that house cats can rarely catch Covid-19 is also not surprising, experts say.
Domestic cats were found to be susceptible to SARS during that outbreak, said Gilles Guillemin, a professor of neuroscience at Macquarie University, who has also studied coronaviruses.
“But there was no indication during the SARS pandemic that SARS-CoV became widespread in house cats or was transmitted from cats to humans,” Guillemin said.
Nor is it any reason to worry that your cat (or your neighbour’s) might be able to infect you or other cats with coronavirus, experts say.
“There is no evidence that naturally infected cats can shed virus in sufficient quantity either to infect other cats or people,” said Ken Smith, a professor of companion animal pathology at the Royal Veterinary College in London.
“These occasional instances of human to animal transmission of Covid-19 do not in any way detract from the fact that all current evidence shows that the pandemic is driven by human to human transmission,” Smith said.
What to do
While it’s highly unlikely that you can give Covid-19 to your cat if you are sick with the virus, experts say we should be following common sense guidelines.
“Contact between infected people and other animals should be minimised,” Smith said. “Specifically, basic hygiene measures should always be implemented. This includes hand washing before and after being around or handling animals, their food, or supplies, as well as avoiding kissing, licking or sharing food.”
And if you know you’re not sick, you can continue to cuddle up close. “I’m still embracing my cat and dogs,” Williams said.