Major variant of coronavirus first found in animals Science

By David GrimmTue 19, 2021 at 4:10 PM

ScienceCOVID-19 reports are supported by the Heising-Simons Foundation.

The variants of SARS-CoV-2 that continue to emerge are not just a human problem. Two reports published this week found the first evidence that dogs and cats can be infected with B.1.1.7, a recent variant of the pandemic coronavirus that spreads more easily between people and also appears to be more deadly in them. The findings mark the first time that one of many major variants of concern has been seen outside of humans.

B.1.1.7 was first identified in the UK and this is where some of the pets infected with the variants were found. British animals suffered from myocarditis – an inflammation of heart tissue which in severe cases can cause heart failure. But reports offer no evidence that the SARS-CoV-2 variant is responsible, nor that it is more transmissible or dangerous in animals. “It’s an interesting hypothesis, but there is no evidence that the virus is causing these problems,” says Scott Weese, a veterinarian at the Ontario Veterinary College at the University of Guelph who specializes in in emerging infectious diseases.

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Since December 2020, scientists have identified several worrying variants that appear to be more transmissible or are able to evade a certain immune response. B.1.351, for example, was first detected in South Africa, and a strain called P.1 was first found in Brazil. Variant B.1.1.7 quickly gained attention due to its rapid growth in the UK; it now accounts for about 95% of all new infections out there.

So far, the impact of these variants on pets is unclear. Although there are now more than 120 million cases of COVID-19 worldwide, only a handful of pets have tested positive for the original SARS-CoV-2 – likely because no one is testing them. Infected pets appear to have symptoms ranging from mild to nonexistent, and infectious disease experts say pets likely play only a limited, if any, role in the spread of the coronavirus to humans.

The new variants could change this equation, explains Eric Leroy, a virologist at the National Research Institute for Sustainable Development, specializing in zoonoses. In one of the new studies, he and his colleagues analyzed pets admitted to the cardiology unit at the Ralph Veterinary Referral Center on the outskirts of London. The hospital had noticed a sharp increase in the number of dogs and cats with myocarditis: from December 2020 to February, the incidence of the disease rose from 1.4% to 12.8%.

This coincided with a push for the B.1.1.7 variant in the UK. So the team examined 11 pets: eight cats and three dogs. None of the animals had a history of heart disease, but all had symptoms ranging from lethargy and loss of appetite to rapid breathing and fainting. Lab tests revealed heart abnormalities, including irregular heartbeats and fluid in the lungs, all symptoms seen in human cases of COVID-19.

Seven of the animals underwent polymerase chain reaction tests and three came back positive for SARS-CoV-2 – all with the B.1.1.7 variant, the team reported yesterday on the bioRxiv preprint server. . Anti-SARS-CoV-2 antibody tests on four of the other animals found that two of them had been infected with the virus. Earlier this week, researchers at Texas A&M University detected the B.1.1.7 variant in a cat and dog from the same house in Brazos County, state.

The Texas owner was diagnosed with COVID-19, and the owners of five of 11 British pets tested positive for SARS-CoV-2, all before their animals developed symptoms. The Texas animals did not show any symptoms at the time they were tested, although they both started sneezing several weeks later. All animals in the US and UK have since recovered, although one of the UK cats relapsed and had to be euthanized.

Leroy says it’s not clear whether B.1.1.7 is more transmissible than the original strain between humans and animals, or vice versa. It is “impossible to say” that pets infected with B.1.1.7 could play a more serious role in the pandemic, he adds, but “this hypothesis needs to be seriously raised.”

Shelley Rankin, a microbiologist at the University of Pennsylvania School of Veterinary Medicine, points out that the researchers only showed a correlation between B.1.1.7 infection and myocarditis, and that they did not not excluded other causes of the disease. “There is no evidence that the pets were sick from the virus,” she says.

Weese agrees that neither the Texas nor the UK results should sound the alarm on pets endangering their owners. “The risk of them being a source of infection remains very low,” he says. “If my dog ​​has it, he probably has it from me. And I’m much more likely to infect my family and my neighbors before him.

Still, he says scientists and vets should do studies on the role, if any, of SARS-CoV-2 and its variants in myocarditis in companion animals. There is evidence that the virus can cause illness in humans, Weese notes, so it’s worth exploring in pets. “It might be real,” he said, “but there’s no reason people are panicking right now.”