Bronx Zoo's former chief pathologist isn't surprised tiger has coronavirus. Here's what pet owners should know
Animal lovers across America were unnerved after it was announced Sunday that a tiger in New York’s Bronx Zoo tested positive for the coronavirus. Nadia, a Malayan tiger, was diagnosed with COVID-19 after showing symptoms of a dry cough and loss of appetite. Several other tigers and lions have shown symptoms of respiratory illness and are presumed infected.
Although some experts say it’s unlikely pets can get or transmit COVID-19, Yahoo Lifestyle spoke with Dr. Tracey McNamara, former chief pathologist at the Bronx Zoo, to get some answers. Dr. McNamara played a crucial role in investigating 1999's West Nile virus outbreak and was also a scientific adviser on the 2011 film Contagion. She tells Yahoo Lifestyle she is “not at all” surprised a tiger tested positive.
“That brings up all sorts of issues that I’ve been trying to address for two months. When you’re dealing with a new disease that can spread between [animal and humans] — it’s a zoonotic disease — I don’t know why anyone would think it’s only between bats and pangolins,” Dr. McNamara, who is involved in efforts to combat the coronavirus pandemic, stated.
Zoonotic diseases are caused by germs that spread between animals and people. Researchers concluded COVID-19 developed naturally, likely from the recombination of a virus found in bats and another virus, possibly originating from pangolins (also known as scaly anteaters).
“With West Nile virus, people did the same thing, thinking only people or only crows until we proved it was in alligators, it was in snow leopards.” she continued. “Seek and you shall find.”
Dr. McNamara, who is currently a professor at the College of Veterinary Medicine at Western University in California, knew it was only a matter of time before the U.S. had its first confirmed case in an animal.
“Many people have been saying — WHO (World Health Organization), CDC (Centers for Disease Control and Prevention), OIE (World Organisation for Animal Health) — that there’s no concern about pets and my answer was, absence of evidence is not at all the same thing as evidence of absence,” she said.
Public health officials believe the big cats at the Bronx Zoo contracted COVID-19 from an employee. Dr. Paul Calle, the current chief veterinarian there, told the New York Times they are operating under the assumption it was a human-to-cat transmission. “That one of the keepers who was asymptomatic or shedding the virus before they were sick was the source of the infection,” Dr. Calle explained.
When asked if she believes that to be true, Dr. McNamara said “maybe.”
“I wouldn’t assume … unless that single keeper was the only keeper working with all of those cats, I would say that would be unlikely,” she replied, explaining one animal could have passed it to another. However, Dr. McNamara emphasized that nothing is known at this point about human-to-animal transmission or animal-to-human transmission “because no one wants to look at it.”
“It’s what I call the ostrich effect, where people are thinking, Oh my God, don’t even go there because what if we find something! Well, if we find something, then we develop a vaccine,” she said.
One scientific study in China determined the virus “replicates poorly in dogs, pigs, chickens, and ducks, but efficiently in ferrets and cats.” It also concluded the virus transmits in cats via respiratory droplets. (The study was done in laboratory conditions.) A different Chinese study found that cats were infected with the coronavirus in Wuhan during the outbreak. While both studies are a start in understanding COVID-19 in animals, Dr. McNamara explained more research needs to be done.
“We have to recognize [the studies] were not peer reviewed, they were small studies and they would have to be repeated, validated and then we will be able to answer some of the questions that everyone is asking,” she explained. “Until that work is done, we can’t answer those questions [about transmission].”
While cats are clearly susceptible to COVID-19, Dr. McNamara said it “would be foolhardy to make predictions” as to what types of animals could be considered at risk for the virus.
“We have no idea in all these other species whether they have receptors that have been implicated with susceptibility to COVID-19 infection,” she said. “It’s called the ACE2 receptor, and they’ve shown how the virus gets into the cells. Cats have those receptors.”
Dr. McNamara added, “Dogs can get infected, but they do not appear to be anywhere near as susceptible as cats.”
According to the American Veterinary Medical Association, there are two dogs and two cats living with people diagnosed with COVID-19 that have been reported to have been infected, as of Monday.
As for symptoms to look out for in pets, Dr. McNamara pointed to confirmed cases of COVID-19 in cats in other parts of the world.
“The first positive cat in Belgium, it developed respiratory and GI (gastrointestinal) signs. The cat had trouble breathing and it also had diarrhea. So, that’s a clue that’s something you have to look for,” she said.
One of the Chinese studies supported that evidence.
Dr. McNamara continued, “Wishing something isn’t so doesn’t make it go away. You just have to meet it head on, figure out what’s going on and then come up with a way to deal with the disease in dogs and cats. The other thing is, through all of this, the only thing people have been looking at is how will this impact humans. Well, what about the animals? Even if there is no transmission between pets and people, that doesn’t mean pets aren’t going to get sick. That in and of itself is reason alone to be able to investigate and figure out what’s going on.”
The animals infected with COVID-19 at the Bronx Zoo are all expected to recover. “Thank goodness,” Dr. McNamara said.
While there are no known cases of the coronavirus in pets in the U.S. yet — the United States Department of Agriculture released a statement warning people who are sick to keep their distance from animals.
“Anyone sick with COVID-19 should restrict contact with animals, out of an abundance of caution including pets, during their illness, just as they would with other people,” the USDA said. “Although there have not been reports of pets becoming sick with COVID-19 in the United States, it is still recommended 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.”
For the latest coronavirus news and updates, follow along at https://news.yahoo.com/coronavirus. According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC and WHO’s resource guides.
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