Natural SARS-CoV-2 infections, including virus isolation, among serially tested cats and dogs in households with confirmed human COVID-19 cases in Texas, USA

Abstract

The natural infections and epidemiological roles of household pets in SARS-CoV-2 transmission are not understood. We conducted a longitudinal study of dogs and cats living with at least one SARS-CoV-2 infected human in Texas and found 47.1% of 17 cats and 15.3% of 59 dogs from 25.6% of 39 households were positive for SARS-CoV-2 via RT-PCR and genome sequencing or neutralizing antibodies. Virus was isolated from one cat. The majority (82.4%) of infected pets were asymptomatic. Re-sampling of one infected cat showed persistence of viral RNA at least 32 d-post human diagnosis (25 d-post initial test). Across 15 antibody-positive animals, titers increased (33.3%), decreased (33.3%) or were stable (33.3%) over time. A One Health approach is informative for prevention and control of SARS-CoV-2 transmission.

Fig. 1.

Multi-pet households in which at least one pet in the house was initially positive by PCR analyses or virus neutralization. All pets in the household were followed longitudinally to track duration of positive test results and changes in antibody titers over time. PCR status is based on preliminary screening Ct of <40 on RdRp, E, N1 and/or N2 gene target from any diagnostic swab type [respiratory (nasal/oral/conjunctival), rectal], or body swab; positive results here do not necessarily indicate USDA case definition has been met. Virus neutralization titer was determined by a two-fold serial dilution of sera.

Fig. 2.

Phylogenetic analysis of SARS-CoV-2 whole genome sequences obtained from three cats and one dog from this study (red; animal ID: TAMU-013, 057, 077, 078) and SARS-CoV-2 genomes from feline and canine hosts based on prior studies (blue) and from humans from Texas (black). The analysis used RAxML with the GTRCAT model (25).