The Emergence and Evolution of Porcine Sapelovirus: Insights from Genomic Surveillance and Recombination Analysis in China

Porcine sapelovirus (PSV) is an emerging enteric pathogen associated with diarrheal disease in pigs, yet its epidemiological characteristics and genomic diversity in China remain inadequately characterized. In this study, we systematically compiled epidemic data on all Chinese PSV strains reported in domestic and international literature and constructed a geographic distribution map of PSV across China. Analysis of co-infection patterns revealed that PSV frequently co-occurs with PEDV, PAstV, and PKoV. A total of 74 PSV Chinese strains were retrieved from GenBank for genomic characterization. No distinct regional clustering was observed among the prevalent strains; however, a remarkably high recombination rate of 85.14% was identified, with recombination breakpoints predominantly concentrated near the 2A gene region. Temporal phylogenetic analysis indicated that avian sapeloviruses and PSV shared a similar evolutionary timeline (1985), with PSV-1 emerging earlier than PSV-2. Within the PSV-1 subtype, the German strain exhibited the earliest divergence (1997), followed by Chinese strains (1985), then Korean and American strains (2005). These findings underscore the importance of sustained genomic surveillance and highlight the need for further investigation into the pathogenicity of circulating recombinant strains and their roles in polymicrobial infections, which is critical for developing effective control strategies.