Cross-Species Transmission of SARS-CoV-2 From Dogs to Hamsters and Pathological Changes in the Brain.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), COVID-19 causative agent, infects several species. Although COVID-19 was reported in some dogs, their roles in transmitting SARS-CoV-2 to other species remain unclear. We investigated the ability of COVID-19 infected dogs to transmit SARS-CoV-2 virus to hamsters and assessed associated pulmonary and neuropathological changes in hamsters. SARS-CoV-2-negative hamsters were placed in close proximity to infected dogs, and viral infection in hamsters was confirmed by infection-associated histopathological changes. SARS-CoV-2 exposure led to notable neurological effects in hamsters, including blood-brain barrier damage, activated immune response, and neurodegenerative changes. This study is the first one to confirm that dogs can transmit SARS-CoV-2 to other species and demonstrates that cross-species viral transmission can contribute to central nervous system pathology and promote neurodegenerative processes. These findings underscore the importance of further investigating dog-to-other species transmission pathways and early-stage neuropathological impacts of SARS-CoV-2 infection.