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June 15, 2020

Researchers look at role of pets in COVID-19 transmission

Published on May 28, 2020

Following reports of a small number of pets testing positive for the COVID-19 virus, researchers want to better understand what part our companion animals might, or might not, play in the epidemiology of the novel coronavirus.

There is little to no evidence that domestic animals are easily infected with SARS-CoV-2 under natural conditions and no evidence to date that they transmit the virus to people.

The U.S. Department of Agriculture put to rest speculation that a pet Pug had contracted the COVID-19 virus. Confirmatory testing by the USDA National Veterinary Services Laboratory was unable to verify infection in the dog, according to a May 27 statement from the USDA. "No virus was isolated, and there was no evidence of an immune response using the available test. The weak detection by PCR (polymerase chain reaction) from the original oral swab may be the result of contamination from the COVID-19 positive household," the department said.

Researchers at the University of Washington and the University of Guelph are calling on pet owners to participate in their respective studies.

University of Washington

“There is no evidence to date of household pets infecting humans with COVID-19,” said Peter Rabinowitz, MD, professor in the University of Washington Department of Environmental & Occupational Health Sciences and Department of Global Health, in a press release.

“But we need to understand the risk better and help people with good preventive practices to avoid transmission between people and animals.”

As of press time, Dr. Rabinowitz and his colleagues at the UW Center for One Health Research and the Washington Animal Disease Diagnostic Laboratory at Washington State University were recruiting participants for a pilot study of people who have tested positive for COVID-19 and their pets.

Researchers are assessing the types of contact owners have with their pets and whether such contact could lead to transmission of the virus.

They want more evidence about what factors lead to any kind of transmission between humans and animals, as well as how much transmission may be occurring. “We expect that such transmission will be rare but we need evidence about that,” Dr. Rabinowitz said.

The researchers hope to test 200 households in King County, Washington, with COVID-19 patients and the animals that live in those households.

Participants complete a survey about contact with their cats, dogs, ferrets, hamsters, or other pets—including whether the pet owners are isolating themselves from pets or whether pet owners are washing their hands before and after touching pets.

The survey also asks about more intimate ways some of us interact with our pets—such as sleeping with them and kissing them.

Veterinarians on the team will test pets for the novel coronavirus and antibodies to the virus by taking nasal and oral swabs and blood samples. The samples will be analyzed at WADDL.

Study participants will receive the test results, and any positive test results will be shared with state officials.

University of Guelph

Dr. Dorothee Bienzle, a professor in the pathobiology department at the University of Guelph Ontario Veterinary College, and her colleague Dr. Scott Weese are studying pets that have been living with a person who tested positive for the COVID-19 virus or who has had symptoms of infection, including a fever and cough.

The researchers are asking owners of cats, dogs, and ferrets to have their pets swabbed and tested to determine whether there is a chance the novel coronavirus could transmit from humans to pets.

“We are conducting a surveillance study swabbing cats, ferrets, and dogs that live in households of persons with a recent diagnosis or symptoms consistent with COVID-19,” Dr. Bienzle said. “The purpose is to determine how frequently pets have SARS-CoV-2 infection, what sites most frequently yield positive PCR results, and how often seroconversion occurs.

“Through a companion surveillance questionnaire, we will capture how long pets and persons continue to experience symptoms and whether they have reoccurrence of symptoms.”

Researchers are collecting samples through nasal swabs similar to those used on humans. Fur samples and rectal swabs are also being collected because, Dr. Bienzle says, there has been evidence to show the virus is spread through feces.

Dr. Bienzle noted that there are only a few cases where animals have become sick with the virus.

OVC will collect samples from pets in the Guelph and Waterloo region as well as the Mississauga and Burlington region, both in Ontario.