Can asymptomatic cats be carriers of coronavirus?
Previously experts had downplayed the possibilities of pets infecting humans with the novel coronavirus, But a new experiment by Dr Peter J. Halfmann and team has shown that there is a possibility that infected cats can infect other cats while remaining completely asymptomatic.
A lab experiment has shown that cats can spread the new coronavirus to other cats without any of them ever having symptoms, Associated Press reported.
Scientists who led the work, reported on Wednesday, said it shows the need for more research into whether the virus can spread from people to cats to people again.
However health experts and veterinary doctors have rejected this idea. The American Veterinary Medical Association said in a new statement that just because an animal can be deliberately infected in a lab "does not mean that it will easily be infected with that same virus under natural conditions."
Anyone concerned about that risk should use "commonsense hygiene," virus expert Peter Halfmann told Associated Press. Don't kiss your pets and keep surfaces clean to cut the chances of picking up any virus an animal might shed, he said.
The Centers for Disease Control and Prevention (CDC), America admits that there have been a very small number of pets, including dogs and cats, reported to be infected with the novel coronavirus after close contact with people with COVID-19. The CDC had received two reports of cats becoming mildly sick with COVID-19 in the United States.
But the CDC had said that there is no evidence that pets can spread the virus to people.
Last week World Health Organisation scientist Dr. Peter Ben Embarek, in his briefing, had said, "So far research has shown that felines such as cats and tigers are susceptible to the virus. Study has also shown that cats can also transmit the disease to other cats. So it is this group of animals that is interesting to look at. Dogs to some extent but not as efficiently, and other domestic species like pigs and poultry, chicken, and turkey does not seem to be susceptible to the disease which is good news because we are producing these animals in a very large scale."
The Findings of the Experiment
Halfmann and colleagues at the University of Wisconsin School of Veterinary Medicine led the lab experiment and published results Wednesday in the New England Journal of Medicine.
Researchers took coronavirus from a human patient and infected three cats with it. Each cat then was housed with another cat that was free of infection. Within five days, coronavirus was found in all three of the newly exposed animals.
All the six cats remained asymptomatic.
"There was no sneezing, no coughing, they never had a high body temperature or lost any weight," Halfmann said. "If a pet owner looked at them ... they wouldn't have noticed anything."
Last month, two domestic cats in different parts of New York state tested positive for the coronavirus after mild respiratory illnesses. They were thought to have picked it up from people in their homes or neighborhoods.
Some tigers and lions at the Bronx Zoo in New York also had tested positive for the virus, as have a small number of other animals around the world.
Those cases and the new lab experiment show "there is a public health need to recognize and further investigate the potential chain of human-cat-human transmission," the authors wrote.
"Moreover, cats may be a silent intermediate host of SARS-CoV-2 (asymptomatic carrier), because infected cats may not show any appreciable symptoms that might be recognized by their owners," read the research findings.
Guidelines from the U.S. Centers for Disease Control and Prevention say that based on the limited information available so far, the risk of pets spreading coronavirus to people "is considered to be low."
The veterinary medicine group says "there is no evidence to suggest that animals, including pets, that may be incidentally infected by humans are playing a role in the spread of COVID-19." It stressed that person-to-person transmission was driving the global pandemic.
However, the group noted that many diseases spread between pets and people, so hygiene is always important: Wash your hands before and after touching pets and keep your pet and its food and water bowls clean.
Halfmann, whose two cats sleep near him, said the worry may be greater for animal shelters, where one infected animal could pass the virus to many others.