It’s that one darn dog.

The one in Hong Kong who tested “weak positive” for SARS-CoV-2 on February 28. And again on February 29. And again on March 2 and yet again on March 5.

He’s the same dog (reportedly a 17-year-old Pomeranian) who keeps getting mentioned in news reports dealing with the question of whether or not companion animals can catch COVID-19 from people. And he’s got people worried.

Because while most experts agree that there’s no evidence that pets can either catch or transmit COVID-19, that one dog’s got a lot of people hedging their bets.

NEWStat reached out to Gail Golab, PhD, DVM, MANZCVS, DACAW, chief veterinary officer of the American Veterinary Medical Association (AVMA) to find out the latest on the science behind that particular Pomeranian outlier.

Golab said the Agriculture, Fisheries, and Conservation Department tested samples from the dog’s nasal and oral cavities using a real time reverse transcriptase polymerase chain reaction (PT PCR) test. “The PT PCR test is sensitive, specific, and does not cross-react with other coronaviruses of dogs and cats,” Golab told NEWStat. “‘Weak positive’ suggests a small quantity of SARS-CoV-2 RNA in the samples.” But she points out that the test doesn’t distinguish whether the samples contain intact viruses, which are infectious, or only fragments of the RNA. “To better understand what this finding means, additional testing has been, and continues to be, conducted. Part of that testing is serology to see if the dog is mounting an immune response to the virus.”

An acute phase sample was negative, Golab said, which indicates that there aren’t currently measurable amounts of antibodies to the virus in the dog’s blood. This doesn’t mean the dog is not infected with the virus, because it is not uncommon to have a negative result in earlier stages of infection. “It can take 14 days or more for measurable levels of antibodies to be detected,” she added.

In other words, the jury is still out.

And testing will continue: “Hong Kong officials advised that a second ‘convalescent’ phase sample will be obtained later for further testing,” Golab said. “In addition, gene sequencing of the SARSCoV-2 virus from the dog and its close human contacts has been done and the viral sequences are very similar. Experts from the School of Public Health of the University of Hong Kong and the College of Veterinary Medicine and Life Sciences of the City University of Hong Kong believe the consistency and persistence of the results suggest the virus may have spread from the infected people to the dog in this particular case.” Follow-up serology is pending.

The dog remains in quarantine and continues to show no signs of being ill with COVID-19.

Meanwhile, IDEXX laboratories issued a statement on March 13 saying that they’ve “seen no positive results in pets to date of SARS-CoV-2” after evaluating thousands of canine and feline specimens during validation of a new veterinary test system for the COVID-19 virus. IDEXX said that the specimens were submitted to IDEXX Reference Laboratories for PCR testing.

“These new test results align with the current expert understanding that COVID-19 is primarily transmitted person-to-person and supports the recommendation against testing pets for the COVID-19 virus,” the statement continued. “For dogs or cats presenting with respiratory signs, the recommendation is to contact a veterinarian to test for more common respiratory pathogens.”

NEWStat contacted Shelley Rankin, PhD, a professor of clinical microbiology and head of Diagnostic Services at University of Pennsylvania Matthew J. Ryan Veterinary Hospital, and asked her about speculation that while the virus may have been present on the dog in Hong Kong (a new study says the virus can live on some surfaces for up to 72 hours), the dog did not actually have the virus.

Rankin doesn’t give that line of thinking much credence: “If there’s no evidence of transmission to pets, then speculating about people getting infected from touching the surface of [an] animal is just that—pure speculation,” Rankin said. “It is not based on any scientific evidence.”

That said, Rankin doesn’t think the dog in Hong Kong should keep pet owners up at night, even if the jury is still out.

“The current understanding among the veterinary microbiology and epidemiology communities is that a single case in a dog is not good evidence that the SARS-CoV-2 virus can be transmitted from humans to animals,” Rankin said. “I have seen no reports of pet to human transmission from any sources.”

Photo credit: © iStock/Viktoriia Hnatiuk