Veterinarians warn of a possible link between a new variant of the coronavirus and heart problems in cats and dogs after an increase in pets with myocarditis at a specialist veterinary clinic in Buckinghamshire during the second wave of the pandemic.
“We don’t want to spread panic unnecessarily, especially because we currently have strong suspicions of human-to-pet transmission, but not the other way around – and we don’t know for sure. However, veterinarians should be aware of this so that they can begin testing if they suspect a possible case of Covid infection, ”said Luca Ferasin, cardiologist at the Ralph Veterinary Referral Center (RVRC) in Marlow, Buckinghamshire conducted the research. which has not yet been assessed by experts.
The highly transmissible variant of B117 was first detected in Kent in December and has quickly become the dominant circulating variant in the UK, accounting for around 95% of infections. It has been detected in at least 85 other countries around the world.
Although cats and dogs are known to have been infected with previous variants, their symptoms were mostly respiratory: runny nose, cough, sneezing, or conjunctivitis. The Buckinghamshire cases are among the first documented animal infections with variant B117.
Ferasin and his team are asking colleagues to look out for cats or dogs with symptoms of heart failure and have them tested for coronavirus – especially if their owners have recently been infected. The vets hope this will help them better understand how the new variant will affect the two animals and what role they may play in transmitting the virus.
Between December and February, Ferasin and colleagues noted an increase in the proportion of dogs and cats enrolled in the RVRC with myocarditis (inflammation of the heart muscle). The number of cases wasn’t huge – just 18 in total – but almost ten times the number at the veterinary clinic this time of year.
The animals were referred after symptoms suggestive of heart failure developed, including lethargy, loss of appetite, rapid breathing or shortness of breath, and severe life-threatening arrhythmias (irregular heartbeat). Two of the cases involved fainting. Further tests showed that they had myocarditis.
This increase in cases reflected the curve and history of human Covid-19 cases controlled by the B117 variant at the time. In most cases of myocarditis, the owner had Covid symptoms or positive tests three to six weeks before their pet became ill. Many of the pets have also tested positive for coronavirus.
In contrast to previously documented Sars-CoV-2 infections in cats and dogs, the animals referred to the RVRC had no other respiratory symptoms.
Ferasin wondered if these heart abnormalities could be related to the rise in cases of Covid in humans, taking blood samples and swabs from the noses, throats and rectums of six cats and a dog with myocarditis between late January and early February. These were tested for Sars-CoV-2 or antibodies against the virus. They also took blood samples from two cats and two dogs who were recovering from myocarditis in the intensive care unit. Of the 11 animals, two cats and a dog tested positive for the virus in their rectal samples, and two other cats and a dog had antibodies to Sars-CoV-2 in their blood. It’s possible that more would have tested positive if those tests had been done earlier, Ferasin said.
With the exception of one cat, which eventually had to be weaned, all animals recover well after medical treatment. Covid has also been linked to heart damage in humans.
However, it is not yet clear whether the virus caused the animals’ symptoms, said Margaret Hosie, a professor of comparative virology at the University of Glasgow’s Center for Virus Research. “It is impossible to rule out that the shedding of Sars-CoV-2 was an incidental finding, and it is inevitable that an animal population proposal will test positive [antibodies to coronavirus] coincides with the peak of the second wave, ”she said.
At the present time it is also impossible to say what proportion of the animals infected with the B117 variant could develop these heart problems. “We’re a bit biased because we only see heart patients and we only see the critical ones,” said Ferasin. “My advice would be if people suspect something is wrong with their animal, they should contact their vet.”
So far, only three other cases of the B117 variant in pets have been reported in the past few days: a cat and dog from the same household in Texas and a cat in Italy. In both households, the owners had also tested positive with B117.
Mick Bailey, Professor of Comparative Immunology at the University of Bristol, said: “The ability of the previous strains to infect cats and dogs has been demonstrated both in the UK and elsewhere. Ferasin’s article shows that B117 can also infect cats and dogs, but that shouldn’t surprise us. Also, given that it appears to be more easily transmitted in humans, we shouldn’t be surprised if it could infect cats and dogs better.
“While animal-to-human infection is theoretically possible, the success of blocking human-to-human social interactions strongly suggests that animal-to-human interactions are not a major problem.”
Hosie said, “The message to pet owners is the same. If you have Covid-19, be aware that it can be transmitted to pets. Avoid contact with your pet and, if this is not possible, wear a mask, for example when preparing the pet food. “