The announcement that two cats in New York have tested positive for the coronavirus has refocused attention on the possible transmission of the respiratory disease between pets and their owners.
The house cats, which live in two separate areas of New York state, are believed to have contracted the coronavirus from people in their households or neighborhoods, the Centers for Disease Control and Prevention and U.S. Department of Agriculture reported Wednesday.
Both had mild respiratory illness, and are expected to make a full recovery, officials said.
Coronavirus infections have been reported in very few animals worldwide, mostly in those that had close contact with a person with COVID-19.
While it appears that domestic animals can be infected, “there is no solid evidence thus far that the SARS-CoV-2 virus can be transmitted from a pet to a human — need lots of careful and difficult research,” said Dr. Craig Carter, a veterinary science and epidemiology professor at the University of Kentucky.
The coronavirus cases in pets follows reports of seven tigers and lions testing positive at the Bronx Zoo.
Here’s what animal experts and studies say about pets and the new coronavirus:
χ Health officials in Hong Kong said 17 dogs and eight cats with COVID-19 patients had been tested for the disease. None of the cats was infected or had been sick, but evidence of the virus was found in two dogs although neither became sick.
A separate report from Hong Kong shows a cat testing positive. Belgium also has reported a case of an infected cat. And researchers in China found that ferrets were susceptible to COVID-19.
“Because COVID-19 is such a new virus, we have very limited information about how it interacts with animals. Currently, we’re seeing human-to-human transmission with rare reports of cats and dogs who are owned by a COVID-infected patient being infected,” said Dr. Annette O’Connor, chair of Michigan State University’s Department of Large Animal Clinical Studies.
The CDC says there is no evidence that pets with COVID-19 can infect people.
“We currently have no evidence that owners can get COVID-19 from cats or dogs because we have no evidence that these animals, when naturally infected, shed the virus,” said Dr. O’Connor.
Dr. O’Connor said while there is evidence that cats can catch COVID-19 from other cats, citing a study involving 102 cats in Wuhan, China, there is only “a small amount of evidence right now.”
Fifteen of those 102 cats tested positive for antibodies to the coronavirus, indicating previous exposure to it. It’s unknown how the cats became infected, Dr. O’Connor said, and more data is needed.
Another group of researchers in China directly exposed a number of cats and dogs with coronavirus by placing large doses of live SARS-CoV-2 into their noses and placing these animals next to uninfected control animals.
Kittens and adolescent cats can become infected, the researchers found, when given a large dose of the virus, Drs. O’Connor, Sargeant and Totton wrote for The Conversation. All five kittens who were exposed became sick and two died. However, adolescent cats were able to fight off the infection without serious illness. The researchers also found that dogs were much more resistant to the coronavirus.
Dr. Carter said there are several varieties of coronaviruses in domestic animals, and that most of them cause digestive system disorders.
If a pet became infected, Dr. O’Connor said people can expect symptoms like diarrhea, vomiting or respiratory issues. She said anyone concerned for their pet should isolate the animal and contact their veterinarian.
χ Chinese health officials say the coronavirus originated from an animal market in the central city of Wuhan. Both severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) are zoonotic diseases, meaning they are transmitted between animals and people.
The source of the new coronavirus is unknown, although researchers have suggested it started with bats. SARS started with bats before jumping to civet cats and then to humans. MERS began in camels before transmitting to humans.
There are no reports of transmission of SARS from cats to dogs to humans or vice versa, according to Dr. O’Connor. She said studies that looked at dogs and cats found that no dogs tested positive while roughly 10% of cats did, but no transmission to humans was reported.
Dr. Carter said he doesn’t know of any data regarding transmission between humans and MERS. He also noted attempts to infect various animals such as sheep, goats and horses with MERS virus were unsuccessful.
“Ferrets and domestic cats can be infected in the laboratory and also shed virus from their pharynx, indicating that animal to human transmission is possible, but I know of no confirmed reports,” he said.
χ The CDC recommends that sick individuals treat their pets as they would other human household members and isolate themselves from their pets and have another household member take care of the animals if possible.
The agency also says pet owners should not allow their animals to interact with people or animals outside the household and should avoid dog parks or public places where large numbers of people and animals gather.
“The chances of your pet catching the coronavirus from another animal are low. If you take your dog or cat outside, have your pets follow the same rules as everyone else — keep them away from other people and animals. Avoid approaching dogs on leashes — not because of the dog, but because there is usually a human on the other end,” Dr. O’Connor said.
• Shen Wu Tan can be reached at stan@washingtontimes.com.
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