"In practice, after introduction of SARS-CoV-2 in our household, we should see our cat as part of the family regarding virus transmission," said study coauthor Wim van der Poel DVM, Ph.D., Professor of Emerging and Zoonotic Viruses, Wageningen University and Research, in the Netherlands.
Van der Poel and colleagues conducted the study to gain better insight into the risk of COVID-19 infection that could arise from cats infected with SARS-CoV-2. In the study, 16 cats were either directly exposed to SARS-CoV-2 virus obtained from a naturally infected human patient, exposed indirectly from the directly exposed cat or exposed from the pen in which the infected cat was housed. All cats were regularly sampled during the whole study. Nasal samples, oropharyngeal samples, blood samples and environmental samples were tested for SARS-CoV-2. Blood samples were also tested for SARS-CoV-2 antibody development. Cats were sampled for 3 weeks, starting on the day of direct exposure to the virus. Nasal samples and oropharyngeal samples were taken 3 times during this period. Oral and rectal samples were taken 15 times during this period. Transmissions of SARS-CoV-2 between cats, through both direct and indirect contact, were evaluated.
The researchers found that cats are susceptible to SARS-CoV-2 and infected cats can spread the virus to other cats and into their environment. They found that the contaminated environment can be infectious, but this infectiousness decays rapidly.
"SARS-CoV-2 transmission between cats is efficient and can be sustained," van der Poel said. "Infections of cats via exposure to a SARS-CoV-2-contaminated environment cannot be discounted if cats are exposed shortly after contamination.
The mean duration of infectiousness was a little more than 1/3 of a day. The duration of infectiousness was calculated from the periods that virus was detected in excreta (oral/nasal fluid or feces).
"We did not expose humans to the infectious cats. Our animal handlers were always fully protected," van der Poel said. "We must assume that cat owners can be infected by SARS-CoV-2 infected cats since these cats excrete infectious virus."
The researchers said they will continue to study SARS-CoV-2 susceptibility in different animal species and focus on virus transmission risks.
