A brief updated review of the evolution and zoonotic concerns of the Alphacoronavirus suis (FCoV and CCoV) in dogs and cats

This paper reviews the genetic evolution and zoonotic potential of Alphacoronavirus suis (CCoV and FCoV), highlighting the emergence of highly virulent, recombinant variants. CCoV evolved from enteric strain into pantropic variants (e.g., CB/05, CCoV-2c, CCoV10/22) and gaining enhanced virulence, systemic dissemination, and severe clinical signs including lymphopenia. FCoV saw the emergence of the highly virulent FCoV-23 in 2023, which exhibits near-universal progression to FIP, increased neurological involvement, and exceptional direct cat-to-cat transmission efficiency, a major deviation from classical FCoV. The detection of CCoV-HuPn-2018 in humans and ongoing recombination in wildlife confirm the zoonotic potential. Alphacoronavirus suis was historically confined to the veterinary field, and attention to this group, apart from FCoV causing Feline Infectious Peritonitis (FIP), was relatively limited. However, recent emergence of variants exhibiting altered host tropism and direct transmission capability, coupled with the detection of CCoV in humans, necessitates integrated surveillance for pandemic preparedness against these rapidly evolving alphacoronaviruses.