Recent reports from England suggest that there may be a connection between COVID-19 infections in dogs and cats and myocarditis (inflammation of the heart muscles). The cases revolve around the highly transmissible B117 variant that has become the dominant strain of SARS-CoV-2 in the United Kingdom.
We already know that dogs and cats can be infected with SARS-CoV-2, which is the virus that causes COVID-19. Some cases are asymptomatic, while some show signs of respiratory illness. Infected pets that become ill (i.e, develop COVID-19) may show signs including coughing, sneezing, and/or ocular nasal discharge. There is currently no evidence, though, that cats or dogs can transmit SARS-CoV-2 to people.
Between December and February, researchers at the Ralph Veterinary Referral Centre (RVRC) in Marlow, Buckinghamshire, noticed a surge in dogs and cats being admitted to the RVRC with myocarditis, nearly 10 times the normal rate.
The pets that were referred in had symptoms suggesting heart disease, ranging from lethargy, lack of appetite, rapid breathing, and shortness of breath to severe life-threatening arrhythmias (irregular heartbeat). Two of the cases experienced collapsing episodes. Further tests revealed they all had myocarditis. None of these pets showed the classic respiratory signs usually seen in patients with COVID-19.
Most of the affected animals improved dramatically with cage rest, oxygen therapy and diuretic therapy, although one cat died while hospitalized. Some pets needed medications to stabilize their heart rhythms.
In most of these cases of myocarditis, the owners of the pets had experienced COVID-19 symptoms or tested positive three to six weeks before their pet became ill. Many of the pets also tested positive for B117 variant of SARS-CoV-2. This stresses the importance of having someone else care for your pets if you become infected with SARS-CoV-2. If you have no one to help, wear a mask and practice strict hygiene.
The research paper reporting these recent cases of myocarditis in pets infected with the B117 variant of SARS-CoV-2 has not yet been peer reviewed for publication. The researchers stress that, at this point, it has not been clearly established that the virus directly caused the myocarditis, but studies in humans suggest that this may be the case. Follow up studies to investigate this possibility are ongoing.