The novel virus responsible for the coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been shown to predominantly infect humans. However, the virus has also been detected in several animals such as ferrets, minks, wild cats, and domestic dogs and cats.
Cats and minks are considered as the most susceptible species because their angiotensin-converting enzyme 2 (ACE2) receptor is very similar to that found in humans. Although most infected cats are asymptomatic, some may develop disease and even pass on the virus to other animals.
Thus, SARS-CoV-2 may directly impact animal health, and there is a possibility of cats becoming zoonotic reservoirs of the virus. While in humans, neutralizing antibodies for SARS-CoV-2 have been found to inversely correlate with disease severity, reported prevalence of neutralizing antibodies against SARS-CoV-2 in cats varies from 0.2% in Brazil and 0.002% in Germany to 5.8% in Italy and 10.8% in Wuhan, China.
Determining the presence of neutralizing antibodies for SARS-CoV-2 in domestic cats in Peru
Although Peru is one of the countries most affected by the pandemic, no studies had been conducted to investigate SARS-CoV-2 seroprevalence among domestic cats. Recently, researchers from Peru demonstrated the presence of neutralizing antibodies for the receptor binding-domain (RBD) of the SARS-CoV-2 spike protein in cats in Lima, Peru. The owners of the cats in the study had confirmed SARS-CoV-2 infection. This study has been published as a preprint on the bioRxiv* server.
The samples were collected from a serum bank. The median age of the cats was 12 months, and 53.7% (22/41) of the cats were female. The researchers used a commercial competitive ELISA SARS-CoV-2 Surrogate Virus Neutralization Test.
Few case studies of natural infection in cats document severe clinical outcomes, and those that have revealed that co-morbidities likely played a contributing factor in illness or death.”
Results show that SARS-CoV-2 infection among cats is not homogenous and is associated with other health factors
Out of a total of 41 samples, 17.1% (7/41) using the cut-off inhibition value of 30% and 31.7% (13/41) using the cut-off inhibition value of 20% were positive. All cats living in the same house did not have detectable levels of neutralizing antibodies. This shows that exposure to infection is not homogenous. The presence of antibodies could be associated with many other factors, including immunity, health status, and proximity with the infected owner(s).
The results of the study offer compelling evidence of SARS-CoV-2 exposure in domestic cats in Peru. Compared to previously published studies from Italy and Wuhan, China, in which 5.8% of 191 cats and 10.8% of 102 cats, respectively, had neutralizing antibodies, percent seropositivity in this cat population from Peru was high. However, the studies conducted on cats from Italy and China were not exclusively performed on a pet population cohabiting with SARS-CoV-2 infected owners.
Our results show compelling evidence of SARS-CoV-2 exposure in domestic cats, and it is the first report of such an event in Peru.”
Findings suggest that cats can serve as custodians for undetected SARS-COV-2 community transmission
According to the authors, this is the first report of SARS-COV-2 exposure in domestic cats in Lima, Peru. They added that it is very important to monitor SARS-CoV-2 exposure and infection in domestic animals with the help of rapid and affordable serological and molecular assays that are accessible to veterinarians from low-income communities.
Although serum neutralization activity is usually tested using plaque reduction neutralization tests, the commercial assay used in this study shows a high correlation with serum neutralization activity using plaque reduction. It also offers logistical and biosafety advantages for researchers working with limited resources.
Cats can serve as custodians for undetected SARS-COV-2 community transmission, and, in such a scenario, veterinarians can play the role of first-line responders. The authors believe that a limited sample size and a convenience sample do not allow prevalence estimation. Hence, more studies are needed to determine the prevalence of SARS-COV-2 exposure in domestic cats of Lima, Peru.
Cats have the potential to serve as sentinels for undetected community transmission, and in this scenario, veterinarians play a key role as first-line responders.”
bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.