A new study published by Taylor & Francis Group reports that more cats have been infected by COVID-19 than what was previously realized. The researchers discovered that many cats are fighting off the coronavirus with naturally developed antibodies, but may still be at risk of re-infection.
Researchers at the Huazhong Agricultural University in Wuhan, the Chinese city where the pandemic originated, collected blood samples and nasal swabs from 102 cats between January and March 2020.
COVID-19 antibodies were detected in 15 of the blood samples, 11 of which were neutralizing antibodies, or proteins that bind to a virus well enough to block the infection.
According to the researchers, none of the cats actually tested positive for COVID-19, displayed obvious symptoms, or died from an infection.
About half of the cats evaluated for the study were in animal shelters, 41 were in pet hospitals, and 15 cats were owned by COVID-19 patients.
The three cats with the highest levels of antibodies were all owned by individuals who had been diagnosed with COVID-19. There was also evidence that some of the cats in shelters and hospitals had been infected by other cats.
Study lead author Meilin Jin noted that while there is currently no evidence for cat-to-human transmission, precautions should be considered.
“Although the infection in stray cats could not be fully understood, it is reasonable to speculate that these infections are probably due to the contact with SARS-CoV-2 polluted environment, or COVID-19 patients who fed the cats,” said Jin.
“Therefore measures should be considered to maintain a suitable distance between COVID-19 patients and companion animals such as cats and dogs, and hygiene and quarantine measures should also be established for those high-risk animals.”
Upon analyzing the antibodies present in many of the cats, the researchers found characteristics that implied the cats “remain at risk of re-infection.”
The study authors explain that this is a similar transient antibody response to also be observed in humans, and that their study should be used as a “reference for the clinical treatment and prevention of COVID-19”.
“We suggest that cats have a great potential as an animal model for assessing the characteristics of antibodies against SARS-CoV-2 in humans.”
The researchers said that further research is needed to establish the route of COVID-19 from humans to cats.
“Retrospective investigation confirmed that all of antibody positive samples were taken after the outbreak, suggesting that the infection of cats could be due to the virus transmission from humans to cats,” said Jin. “Certainly, it is still needed to be verified via investigating the SARS-CoV-2 infections before this outbreak in a wide range of sampling.”
The study is published in the journal Emerging Microbes & Infections.