We have two cats at home, one of which habitually roams around the neighbourhood. This prompted my mother to have concerns about animals and specifically pets as carriers of the virus so I thought I’d read up a bit on this.
Significant research has been conducted on the SARS-CoV-2 and its infection in humans but little is known about the susceptibility of domestic mammals, such as dogs and cats, to the virus. A leading theory is that SARS-CoV-2 originated in bats and which passed the virus on to an unknown intermediate species that came into contact with people in a wild-animal market in Wuhan. Dogs, cats or other closely related mammalian species could have formed the bridge between bats and humans.
A recent study on dogs [1] from households with confirmed human cases of COVID-19 in Hong Kong has shown evidence of human-to-animal transmission of SARS-CoV-2. Two out of the fifteen dogs who lived with infected people caught the disease. One was a 17 year old male Pomeranian and the other a 2.5 year old male German Shepherd. The viral genetic sequences from the two dogs were identical to the virus detected in the respective human cases. Both animals remained asymptomatic and had developed antibodies against the virus.
Since the infections in the two canines in Hong Kong were reported, other pets have tested positive for the virus too; including two cats in New York and another in Hong Kong. Four tigers and three lions at the New York City’s Bronx Zoo have also tested positive. Studies in cats [2] have also found that they can pass the virus to other felines without showing symptoms. Whether infected dogs can transmit the virus to other animals or back to humans remains unknown.
There is an urgent need to test more animals that are in close contact with people to understand whether they have a role in spreading the virus. The American Veterinary Medical Association recommends that people wear a mask when caring for pets if they are feeling unwell. They should also avoid petting, hugging or sharing food with their, and should wash their hands before and after contact with them.
[1] https://www.nature.com/articles/s41586-020-2334-5_reference.pdf
[2] https://www.nature.com/articles/d41586-020-00984-8
