Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Infection and Humoral Responses Against Different Variants of Concern in Domestic Pet Animals and Stray Cats from North-Eastern Spain

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease 2019 (COVID-19) pandemic in humans, is able to infect several domestic, captive and wildlife animal species. Since reverse zoonotic transmission to pets has been demonstrated, it is crucial to determine their role in the epidemiology of the disease to prevent further spillover events and major spread of SARS-CoV-2. In the present study, we determined the presence of virus and the seroprevalence to SARS-CoV-2, as well as the levels of neutralizing antibodies (nAbs) against several variants of concern (VOCs) in pets (cats, dogs and ferrets) and stray cats from North-Eastern of Spain. We confirmed that cats and dogs can be infected by different VOCs of SARS-CoV-2 and, together with ferrets, are able to develop nAbs against the ancestral (B.1), Alpha (B.1.1.7), Beta (B.1.315), Delta (B.1.617.2) and Omicron (BA.1) variants, with lower titres against the latest in dogs and cats, but not in ferrets. Although the prevalence of active SARS-CoV-2 infection measured as direct viral RNA detection was low (0.3%), presence of nAbs in pets living in COVID-19-positive households was relatively high (close to 25% in cats, 10% in dogs and 40% in ferrets). It is essential to continue monitoring SARS-CoV-2 infections in these animals due to their frequent contact with human populations, and we cannot discard the probability of a higher animal susceptibility to new potential SARS-CoV-2 VOCs.