Lung samples of one of the infected cats revealed damage to the lungs consistent with a viral pneumonia and there was evidence of SARS-CoV-2 infection.
A team of scientists at the University of Glasgow has identified two known cases of human-to-cat COVID-19 transmission in the UK.
In the study, led by the University of Glasgow, researchers describe two cases of human-to-cat SARS-CoV-2 transmission, found as part of a COVID-19 screening program of the feline population UK.
Different breeds
The cats, both different breeds, came from two separate homes and displayed mild-to-severe respiratory symptoms.
Researchers from the Medical Research Council (MRC)-the University of Glasgow Centre for Virus Research (CVR), in partnership with the Veterinary Diagnostic Service of the university’s School of Veterinary Medicine, think both cats were infected by their owners, who were also displaying COVID-19 symptoms before the cats becoming sick.
Ragdoll
The initial cat was a four-month-old female ragdoll kitten from a household in which the owner exhibited symptoms consistent with SARS-CoV-2 infection at the end of March 2020, although the owner was not tested.
The kitten was presented to its veterinary surgeon in April 2020 with trouble breathing; however, the cat’s condition deteriorated, and it later had to be euthanized. Postmortem lung samples later showed damage to the lungs consistent with viral pneumonia, and evidence existed of SARS-CoV-2 infection.
Siamese
The second cat was a six-year-old female Siamese from a household where one owner tested positive for COVID-19.
The cat was brought to the vet with nasal discharge and conjunctivitis, but these clinical signs remained mild, and the cat later recovered.
COVID-19 infection was demonstrated in the cat as part of a UK-wide COVID-19 feline screening program, and the APHA confirmed this.
Mutations
Researchers at the CVR completed full genome sequencing of the SARS-CoV-2 genome in cat two and found it was quite similar to viral genomes circulating in humans.
The researchers found no indication of species adaptation in the cat’s viral sequences. They concluded that any mutations present in cat two’s viral genome were likely also present in the owner’s virus. However, the genome sequence from the owner was not available for observation.
Unknown
At present, no evidence of cat-to-human transmission exists or that cats, dogs, or other domestic animals play any role in the epidemiology of human infections with SARS-CoV-2. Whether cats with COVID-19 could naturally transmit the virus to other animals or back to humans remains unknown.
However, scientists believe these two known cases of human-to-cat transmission in the UK are likely to underestimate the true frequency of human-to-animal transmission, as animal testing is limited.
Transmission role
Margaret Hosie from the MRC-University of Glasgow CVR, lead author of the study, said: “These two cases of human-to-animal transmission, found in the feline population in the UK, demonstrate why it is important that we improve our understanding of animal SARS-CoV-2 infection.”
“Currently, animal-to-human transmission represents a relatively low risk to public health in areas where human-to-human transmission remains high. However, as human cases decrease, the prospect of transmission among animals becomes increasingly important as a potential source of SARS-CoV-2 reintroduction to humans.
“It is, therefore, essential to improve our understanding of whether exposed animals could play any role in transmission.”
Susceptible
Since the pandemic began, there have been reports of cats from COVID-19 households in Hong Kong, Belgium, the US, France, Spain, Germany, Russia, Japan, Italy, Chile, Canada, Brazil, Argentina, Switzerland, and Latvia that tested positive for SARS-CoV-2 and were presumed to be infected from their owners.
Naturally occurring SARS-CoV-2 infections have been reported in cats, non-domestic cats, and dogs. Scientists have also shown that cats, ferrets, and hamsters are susceptible.
This study was funded by the Wellcome ISSF COVID Response Fund and supported by the MRC.
