SARS-CoV-2 in domestic UK cats from Alpha to Omicron
Published: 17 October 2023
SARS-CoV-2 can infect numerous mammalian species in addition in humans. Pet cats live closely alongside us and are susceptible, but we don’t yet know the full spectrum of illness that the virus may cause in cats. A team of CVR researchers have screened a large number of domestic cat swabs for SARS-CoV-2. They found that cats have been less susceptible to SARS-CoV-2 since Omicron became the dominant variant and that infected cats show a variety of clinical signs.
SARS-CoV-2 can infect numerous mammalian species in addition in humans. Pet cats live closely alongside us and are susceptible, but we don’t yet know the full spectrum of illness that the virus may cause in cats.
There were several surveys of feline infections earlier in the pandemic but there has been less work on cats more recently. As such large numbers of people have been infected since the Omicron variant emerged, the Comparative Virology Group at the CVR (led by Professor Margaret Hosie), expected a larger number of cats to be infected with Omicron than were infected with the earlier variants, and wanted to test this theory. They also wanted to find out more about how the virus may affect cats.
The team of researchers, led by Dr Sarah Jones, appealed to UK veterinary surgeons to send us samples if they suspected that a domestic cat was sick due to SARS-CoV-2 infection. They also screened nasal/oral swabs that were sent to the university’s Veterinary Diagnostic Services laboratory for other reasons.
The team tested respiratory swab samples using PCR testing and measured antibodies to SARS-CoV-2 in blood samples.
The positivity rate in the swab screening study was less than 1%; the results of this section suggest that cats have been less susceptible to SARS-CoV-2 since Omicron became the dominant variant. It is also possible that they still become infected, but develop milder or no illness, or shed only low amounts of virus that is harder to detect.
The team identified six infected cats that were unwell; one was identified by screening swabs submitted for other reasons and the other five were detected via the appeal to veterinary surgeons for suspected cases. One had the Alpha variant, four had Delta and one had Omicron.
Some cats had only mild signs of disease, but one had a reduced appetite for several weeks after being infected, one had severe respiratory signs, and another died suddenly. Prolonged inappetence and sudden death have not been reported in cats with SARS-CoV-2 before; this demonstrates that clinical signs may be variable, as they are in humans.
The team demonstrated that a variety of clinical signs may occur in infected cats. This will raise awareness of the possibility of SARS-CoV-2 infection in unwell cats.
First published: 17 October 2023