Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the cause of Coronavirus Disease 2019 (COVID-19) and responsible for the current pandemic. Here, we present an in-depth study of SARS-CoV-2 infection, associated disease, transmission and reinfection dynamics in domestic cats. Six 4- to 5-month-old cats were challenged with SARS-CoV-2 via intranasal and oral routes simultaneously. One day post challenge (DPC), two sentinel contact cats were co-mingled with the principal infected animals. Animals were monitored for clinical signs, clinicopathological abnormalities (blood cell counts, serum biochemistry) and viral shedding throughout a 21 DPC observation period. On 21 DPC, three cats were reinfected with SARS-CoV-2. Animals were sacrificed and post mortem examinations performed at 4, 7, 21 DPC and 4 days post second challenge (DP2C) to investigate disease progression in various organ systems and tissues. Viral RNA was not detected in blood but transiently in nasal, oropharyngeal and rectal swabs in principal infected, sentinel and reinfected animals, as well as in bronchoalveolar lavage fluid at 4 and 7 DPC and in various organs/tissues of primary infected and reinfected animals. Lung lesions associated with the presence of viral RNA and antigen were observed in primary infected cats on 4 and 7 DPC, but not on 21 DPC and 4 DP2C. Serology showed that both, principal and sentinel cats developed SARS-CoV-2-specific and neutralizing antibodies to SARS-CoV-2 starting at 7 DPC or 10 DPC, respectively. All animals were clinically asymptomatic during the course of the study; primary infected but not reinfected cats were capable of transmitting SARS-CoV-2 to contact animals within 2 days of comingling. The results of this study are critical: (i) for our understanding of the clinical course of SARS-CoV-2 in a naturally susceptible host species; (ii) for evaluating whether a SARS-CoV-2 infection can protect against reinfection; (iii) for the development of an alternative preclinical COVID-19 animal model; and (iv) for risk assessment of SARS-CoV-2 infections in felines and transmission to other animals and humans.
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