Efficient direct and limited environmental transmission of SARS-CoV-2 lineage B.1.22 in domestic cats

Susceptibility of domestic cats for infection with SARS-CoV-2 has been demonstrated by several experimental studies and field observations. We performed an extensive study to further characterize transmission of SARS-CoV-2 between cats, both by direct contact as well as by indirect contact. To that end, we estimated the transmission rate parameter and the decay parameter for infectivity in the environment. Using four groups of pair-transmission experiment, all donor (inoculated) cats became infected, shed virus and seroconverted, while three out of four direct contact cats got infected, shed virus and two of those seroconverted. One out of eight cats exposed to a SARS-CoV-2-contaminated environment became infected but did not seroconvert. Statistical analysis of the transmission data gives a reproduction number R 0 of 2.18 (95% CI: (0.92-4.08), a transmission rate parameter β of 0.23 day -1 (95% CI: 0.06-0.54), and a virus decay rate parameter μ of 2.73 day -1 (95% CI: 0.77-15.82). These data indicate that transmission between cats can be sustained ( R 0 >1), however, infectiousness of a contaminated environment decays rapidly (mean duration of infectiousness 1/2.73 days). Infections of cats via exposure to a SARS-CoV-2-contaminated environment cannot be excluded if cats are exposed shortly after contamination.