A dog in Hong Kong has a low-level infection of the new coronavirus

A pet dog in Hong Kong has a low-level infection with the new coronavirus that the animal may have gotten from its owner, raising concerns that the virus currently spreading around the world can infect pets (SN: 3/4/20).

But experts say it’s only a single case so far, and there is currently no evidence that pets can actually get sick from the virus or pass it to people or other animals.

“We don’t believe that this is a major driver of transmission,” Maria Van Kerkhove, a technical consultant with the World Health Organization, said in a news conference on March 5. “It’s only one example … and so of course it deserves much more study,” she said.

Nasal and oral swabs from the dog, whose owner was infected with the new coronavirus, called SARS-CoV-2 because of its similarity with the 2003 SARS virus, had tested weakly positive, though the animal wasn’t showing any signs of disease, officials in China announced February 28. Officials from China’s Agriculture, Fisheries and Conservation Department isolated the dog in an animal facility in Hong Kong beginning February 26.

These initial test results could have been the product of environmental contamination of the dog’s nose and mouth as it sniffed and licked contaminated objects and not signs of an actual infection. But a subsequent test of nasal swabs on March 2, after the dog had been quarantined, was also positive. The dog still has not shown any signs of disease related to COVID-19. Another pet dog from another patient is also in quarantine, but has tested negative for the virus.

There’s no current evidence to suggest that dogs can spread the new coronavirus to other dogs or to people, Chinese officials say.

As the dog’s tests are only weakly positive, it could be a dead-end host, meaning that the virus is not replicating at high enough levels in the dog to be transmitted to someone else. The tests also rely on detecting small bits of the virus’s genetic code, which does not measure whether infectious virus that can infect another host is present. Researchers are now analyzing the genetic blueprint of the dog’s virus to learn more about it and where it came from.

“We need to establish quite clearly what part animals might play in transmission. That is unknown,” Michael Ryan, executive director of the WHO Health Emergencies Programme, said in the March 5 news conference. But animals getting infected is “not an unusual or unprecedented finding. It happens regularly with emerging diseases,” he said.   

There are other coronaviruses that infect pets. In dogs, one type can cause intestinal disease, and another is part of a list of various bacteria and viruses responsible for kennel cough. While a vaccine is available for the canine intestinal coronavirus, the American Animal Hospital Association does not generally recommend it, since the infection typically causes mild symptoms in young puppies and clears up on its own.    

Researchers reported in 2003 in Nature that cats could be infected with the coronavirus that causes SARS, or severe acute respiratory syndrome, and transmit it to other cats in the same cage, but they didn’t show any symptoms (SN: 11/18/03). The same was true for ferrets, the researchers found, although the ferrets became sick. There is no evidence that pets played a role in the SARS outbreak.  

As a basic precaution though, the U.S. Centers for Disease Control and Prevention advises that pet owners who are sick should restrict contact with pets. Those who are ill and have to interact with animals should wear a face mask and wash their hands before and after taking care of their pets.