Active surveillance reveals common SARS-CoV-2 infections among cats and dogs from households with human COVID-19 cases in Texas, USA

Households where people have COVID-19 are high-risk environments for companion animals to become infected by SARS-CoV-2. We sampled 579 pets from 281 households with one or more laboratory-confirmed persons with COVID-19 in central Texas from June 2020 to May 2021. Nineteen out of 396 (4.8%) dogs and 21 out of 157 (13.4%) cats were positive for SARS-CoV-2 by RT-qPCR. Additionally, 95/382 (25%) dogs and 52/146 (36%) cats harbored SARS-CoV-2 neutralizing antibodies. Twenty-six companion animals of ten other species were negative. Overall, 164 (29%) pets were positive for SARS-CoV-2 by molecular and/or serological tests; a total of 110 (39%) out of 281 households had at least one animal with active or past SARS-CoV-2 infection. Cats were more likely to be infected by SARS-CoV-2 and had higher endpoint antibody titers than dogs. We detected 11 SARS-CoV-2 lineages and isolated five of them from dogs and cats, including the B.1.234 lineage that was isolated from a cat a few weeks after the first detection in humans in the United States. Detection of SARS-CoV-2 RNA decreased by 10% per additional day post COVID-19 diagnosis of the human case in the household for both dogs and cats, whereas seropositivity odds increased with each additional day. Human-pet interactions associated with a higher risk of infection in dogs and cats included sleeping in the same room as an infected person, living with multiple infected persons, and sharing food with people. The frequency of clinical signs in pets with active infections did not differ from uninfected ones, suggesting that not all reported signs are attributed to SARS-CoV-2 infection. Characterizing animal infections using active SARS-CoV-2 surveillance in pets at risk of infection may aid in One Health pandemic prevention, response, and management.