A recent survey by a team of scientists from France shows that pets living with patients with Confirmed Coronavirus Disease 2019 (COVID-19) have a high prevalence of Coronavirus 2 (SARS-CoV-2) antibodies with severe acute have respiratory syndrome. The study is currently available on the bioRxiv * preprint server.
Since the onset of the COVID-19 pandemic, most studies have shown that SARS-CoV-2 is only transmitted from person to person via respiratory droplets. While there is still no definitive evidence of zoonotic transmission of SARS-CoV-2, previous studies have shown domestic dogs and cats are susceptible to other alpha and beta coronaviruses. In addition, coronavirus epidemiological and biological properties suggest that there is a possibility of pathogen overflow. Given these observations, it’s important to understand whether pets are prone to getting the infection from their SARS-CoV-2 positive owners.
High prevalence of SARS-CoV-2 antibodies in pets from COVID-19 + households. Image Credit: Chaay_Tee / Shutterstock
Current study design
In the current study, the scientists carried out a serological test on pets living with SARS-CoV-2-positive patients between May 2020 and June 2020. The survey was carried out in two regions of eastern France with similar epidemiological status and health policies.
The scientists formed three test groups. 1. A COVID-19 positive household group with pets (dogs and cats) who lived with at least one SARS-CoV-2 positive. 2. symptomatic patients; The household group of unknown status included pets who lived with owners of unknown status. 3. The control group, including pets sampled before the COVID-19 pandemic. To rule out the possibility of cross-reactivity with antibodies, they included serum samples from ten cats infected with peritonitis virus infectious in cats.
They performed three different antibody detection tests on serum samples taken from domestic animals. The results showed the presence of SARS-CoV-2 immunoglobulin G molecules (IgGs) against the nucleocapsid (N) protein and the S1 and S2 subunits of the spike (S) protein. In addition, SARS-CoV-2 specific neutralizing antibodies were detected using a retrovirus-based pseudoparticle assay. The pets with positive results in the seroneutralization test or in all three antibody detection tests were considered to be SARS-CoV-2 seropositive. Since none of the pets in the control group showed seropositive status in antibody detection or seroneutralization tests, the scientists believed that the positivity criteria they followed in the study ensured 100% specificity.
Of 47 pets tested in the COVID-19 positive household group, 10 showed the presence of anti-SARS-CoV-2 antibodies (21%). However, there was no significant difference in seropositivity between dogs and cats. In the household group with an unknown status, a total of 38 pets were tested, only one of which had antibodies against SARS-CoV-2. This indicates that the seroprevalence of SARS-CoV-2 antibodies in COVID-19 positive households is significantly higher than in households with an unknown status. In addition, the scientists analyzed that the risk of SARS-CoV-2 infection in pets with confirmed COVID-19 patients was eight times higher than in pets with owners of unknown status.
Since anti-N antibody tests are known to provide underestimated information about SARS-CoV-2 seropositivity than anti-S antibody tests in the general population, the scientists assumed that the actual percentage of seropositive pets in the current study was 53% would have been. as estimated from the anti-S antibody test results.
The significantly high prevalence of anti-SARS-CoV-2 antibodies in pets with COVID-19 patients suggests that the pets may have been infected by their owners. However, the study cannot provide a definitive answer as to whether seropositive pets were actually infected with SARS-CoV-2.
Given the fact that pets are infected with SARS-CoV-2, the current study results raise an open question as to whether animals can contribute to the COVID-19 pandemic due to the overflow of pathogens from animal to human. The study also emphasizes that people who live in close contact with animals should take the necessary precautions to contain possible zoonotic transmission of SARS-CoV-2.
* Important NOTE
bioRxiv publishes preliminary scientific reports that are not peer-reviewed and therefore should not be considered conclusive, guide clinical practice / health-related behavior, or be treated as established information.