Study shows likely case of virus spreading from cats to humans, but risk remains low


A veterinarian in Thailand likely contracted the coronavirus from an infected cat last year, researchers have concluded in a new study. This is the first documented case of suspected cat-to-human transmission, although experts stress that the risk of cats infecting humans with the virus remains low overall.

One of the cat’s two owners, who both had Covid-19, likely transmitted the virus to the cat, which then sneezed in the face of the vet, according to the paper by scientists from Thailand’s Prince of Songkla. Genomic sequencing confirmed that the cat and the three people were infected with an identical version of the virus, which was not prevalent in the local population at the time.

Cats are much more likely to pick up the virus from people than pass it on to them, scientists say. But the case is a reminder that people infected with the virus should take precautions around their pets – and that vets and shelter workers who may come into contact with infected animals should do the same, Dr. Scott Weese, infectious disease veterinarian. at the University of Guelph in Ontario.

“When things become human diseases, we too often forget everything else,” he said. “I think it’s important for us to recognize that this virus can still move between species.”

Previous research has shown that pet owners can infect their cats, and that under certain conditions cats can transmit the virus to each other. But it has been difficult to prove that cat-to-human transmission occurs in natural environments. (Mink, hamsters and deer have been reported to transmit the virus to humans.)

The new article appeared this week in the journal Emerging Infectious Diseases, which is published by the US Centers for Disease Control and Prevention. This makes a strong case for cat-to-human transmission, Dr Weese said: “They have a pretty good story here.”

On August 4, a father and son in Bangkok developed symptoms of Covid-19 and later tested positive for the virus. Due to a shortage of hospital beds in Bangkok, the two men were taken to a hospital in Songkhla, a province in southern Thailand, on August 8 via a 20-hour ambulance ride. For reasons that are unclear, they brought their pet cat.

When the men were admitted to hospital, the cat was sent to a veterinary hospital for an examination. Although the cat appeared to be healthy, the vet, a 32-year-old woman, took nasal and rectal swabs, which tested positive for the virus. As the vet dabbed the cat’s nose, the animal sneezed into its face. (The vet wore gloves and a mask during the exam, but no face shield or eye protection.)

On August 13, the vet developed symptoms of Covid-19, including fever and cough. Shortly after, she tested positive for the virus.

Genomic sequencing revealed that the cat’s owners, the cat and the vet were all infected with the same version of the Delta variant, which was distinct from viral samples taken from other patients in Songkhla at the time.

PCR tests suggest the cat had a high viral load at the time of its veterinary examination. None of the vet’s close contacts are known to have had Covid-19 at the time, and she had no previous encounters with the pet’s owners, bolstering the theory that the cat was the source. of infection from the veterinarian. (It was unclear if she had met the owners later.)

The CDC recommends people infected with the virus avoid contact with their pets. “If you’re trying to stay away from people because you’re potentially infectious,” Dr. Weese said, “just try to stay away from animals at the same time.”


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