Share on PinterestCan cats and dogs become infected with the alpha variant of SARS-CoV-2? Westend61 / Getty Images
- The researchers conducted a study to see if there was a link between increases in heart inflammation in cats and dogs and SARS-CoV-2.
- They found that the majority of the pets examined got infected with SARS-CoV-2 soon after confirming or suspecting that their owners had the virus.
- The researchers conclude that pets can be infected with the B.1.1.7 or alpha variant of the virus. However, scientists need to do more research to confirm exactly how it affects pets.
Several case reports have surfaced around the world of pets, especially cats and dogs, who have become infected with SARS-CoV-2 in their owners.
Symptoms were mostly mild and included mild digestive and breathing problems such as coughing, runny nose, and sneezing.
Despite a large increase in SARS-CoV-2 cases in the UK since November 2020, there have been no reports of animals infected with the virus.
Tracking the transmission of SARS-CoV-2 to animals is vital to keeping animals safe and preventing the formation of reservoirs of viruses that could perpetuate the pandemic.
Recently, researchers from the UK and France recorded several cases of cats and dogs who appeared to be infected with SARS-CoV-2 in their owners and who developed symptoms of myocarditis, an inflammation of the heart muscle.
“Our study reports the first cases of cats and dogs affected by the COVID-19 alpha variant and, more than ever, highlights the risk that pets can pose [contract] SARS-CoV-2 “, says Dr. Luca Ferasin, DVM, Ph.D., lead study author and head of cardiology at Ralph Veterinary Referral Center (TRVRC) in the UK
“We also reported on the atypical clinical manifestations characterized by severe cardiac abnormalities that are a known complication but never occurred in people affected by COVID-19 [been] previously described for pets. COVID-19. However […] in pets is still a relatively rare condition and our observations indicate that it is transmitted from humans to pets rather than the other way around, ”he adds.
The study appears in the journal VetRecord.
Between December 2020 and February 2021, TRVRC veterinarians noted an increase in cats and dogs with signs of acute myocarditis entering their clinic.
Myocarditis accounted for 12.8% of their cardiac cases, up from around 1.5% the previous year.
In total, they diagnosed 26 cats and dogs with the disease between December 2020 and March 2021.
They observed that this coincided with the peak of the SARS-CoV-2 cases in the UK, suggesting a possible link. To investigate, they asked the owners of these pets if they had had symptoms of COVID-19 in the previous weeks or if they had tested positive for SARS-CoV-2 at any time.
The researchers found that the majority of owners of these pets contracted SARS-CoV-2 3–6 weeks before their pets became ill. The vets decided to test the cats and dogs for the presence of the virus using molecular tests (PCR) and antibodies in the blood.
For this purpose, blood, mouth, nose and throat and rectum swabs were taken from six cats and one dog with suspected myocarditis after direct contact with people in their household with confirmed or suspected SARS-CoV-2. They also collected blood samples from two cats and two dogs during their recovery period.
They sent the samples to the MIVEGEC laboratory at the University of Montpellier in France for molecular testing (PCR) and antibody testing.
Once diagnosed, the vets found that none of the 11 study animals with myocarditis developed flu-like symptoms and that all clinically improved within a few days of intensive treatment. Further diagnostic tests did not reveal any alternative viral, bacterial, or other cause of her myocarditis.
A total of two cats and a dog tested positive in PCR testing, and two cats and a dog had developed antibodies to COVID-19.
The vets also found that all of these pets tested positive for the alpha variant of the virus, which was responsible for the sudden surge in SARS-CoV-2 cases in the UK between December 2020 and March 2021.
The results are consistent with those from a recent case report from France, which provides evidence of a link between transmission of the alpha variant to domestic animals and the development of myocarditis.
“We believe these dogs and cats [contracted SARS-CoV-2] from their owners, as they developed clinical signs a few weeks after their owners developed symptoms of COVID-19 or tested positive for the presence of the virus, “said Dr. Ferasin told Medical News Today.
“All of these pets were presented to our ambulance service because they suddenly experience weakness, loss of appetite, fainting from underlying cardiac arrhythmias, and difficulty breathing due to fluid in their lungs due to their heart disease – congestive heart failure.”
MNT also spoke to Prof. Margaret Hosie, Professor of Comparative Virology at the University of Glasgow in the UK, who was not involved in the study. She said:
“When SARS-CoV-2 infects a person, it binds the ACE-2 receptor to enter the cell and initiate the infection. So in species in which the ACE-2 molecule is similar to the molecule in humans, it is possible that the virus is also [transmissible to] this species. “
“This is the case in cats and dogs because their ACE-2 receptor molecule has a high degree of sequence homology with its human counterpart,” she explained.
“Since ACE-2 is widespread in the body, SARS-CoV-2 infects many organs such as the heart and lungs. In humans and, since the receptor distribution is similar in animals, we might expect similar clinical symptoms in infected animals. To date, however, clinical symptoms in cats have been rather mild respiratory symptoms and the animals recovered uneventfully. Dogs seem less prone to infection and rarely show clinical signs, ”she continued.
Prof. Nicola Decaro from the Department of Veterinary Medicine at the University of Bari Aldo Moro in Italy, who was not involved in the study, told MNT:
“Similar to other animals, cats and, to a lesser extent, dogs are susceptible to SARS-CoV-2 infection, especially if they live in a highly contaminated environment, as are COVID-19 positive households.”
“In a study that was carried out in northern Italy during the first wave of the pandemic, we found SARS-CoV-2 antibodies in 3.3% or households. In other studies, dogs and cats positive for SARS-CoV-2 RNA shed a virus that was genetically identical to that of their owner[s]“Added Prof. Decaro.
“That is why there is contact between human patients [who have contracted SARS-CoV-2] and their pets have been linked to virus transmission to dogs and cats. The observation of clinical symptoms in cats, and particularly in dogs, is infrequent, with most reports indicating the occurrence of a slight respiratory and sometimes [gastrointestinal] Illness.”
“However, it can be assumed that the same pathogenetic mechanisms that are responsible for the occurrence of myocarditis in COVID-19 positive people are also involved in the occurrence of myocardial disease in pets, albeit at a lower frequency,” he continued.
The researchers conclude that pets can be infected with the B.1.1.7 or alpha variant of the virus. However, more research is needed to determine exactly how it affects pets.
“We have seen a rapid decline in myocarditis cases since April this year and are now back at the historic incidence of myocarditis – about 1-1.5% of all our cardiac cases,” said Dr. Ferasin. “We are not sure if the relatively new Delta variant can infect dogs and cats and cause similar heart problems, so we will remain vigilant about this.”
The researchers note some limitations in their results. For example, the diagnoses of myocarditis could not be confirmed due to the risks of invasive surgery. They also point out that it is not possible to say if there is a direct link between COVID-19 and the disease because they have no control group.
In addition, the study included a very small number of animals.
For people who have or think they might have COVID-19, Dr. Ferasin, “Wash hands thoroughly before and after touching your pets, and wear a mask when in close proximity to your dog or cat. If a pet has clinical signs that may be linked to COVID-19, we also recommend contacting their primary veterinarian.
“Owner [who may have contracted SARS-CoV-2] should avoid contact with their animals just as they should avoid contact with other people ”, says Prof. Hosie.
“If there is no one else to take care of their pet, owners should wear a mask when preparing their pet’s food to avoid this [passing on the virus to it]. No cat from one COVID-19 household should not be admitted to another household, ”she continued.
“There is no evidence that the virus can be transmitted from pets to humans, although it would be difficult to collect such evidence and rule out the possibility [transmission] from other sources, ”noted Prof. Hosie.
“It is important that we investigate SARS-CoV-2 further” [cases] in animals, as we do not know how often viruses can be transmitted between animals or whether the disease can be more serious in certain groups of animals. At the moment all efforts are focused on controlling infections in humans, but in the longer term other animal species could create a reservoir of viruses and therefore perpetuate themselves [transmission] in humans, if they are not identified as potential sources of SARS-CoV-2, “she added.
“We need to develop systems to improve the exchange of information between public health and veterinary services in order to better investigate situations in which a person who [has contracted] SARS-CoV-2 reports contact with pets or other animals, ”concluded Prof. Hosie.