First detection of parainfluenza virus 5 in sika deer: Evidence for cross-species transmission and zoonotic potential

This is the authors' abstract. We don't add key points for this paper.

Parainfluenza virus 5 (PIV5), a member of the Paramyxoviridae family, is a widely distributed respiratory pathogen with a broad host range; however, infection in sika deer has not previously been reported. In this study, active surveillance at a sika deer slaughterhouse in Jilin province, northeastern China (October 2024 - March 2025), identified two PIV5-positive samples (0.3%, 2/617). Whole-genome sequencing and phylogenetic analysis confirmed that both viruses clustered within clade 2.4 of group B, the predominant lineage currently circulating in China. Genome comparison revealed high homology with PIV5 strains from swine, ticks, and pangolins. A representative isolate, JL492, was successfully recovered in Vero E6 cells, replicated efficiently across multiple cell lines including human-origin cells, and induced clear cytopathic effects, suggesting the potential for cross-species transmission without prior adaptation and raising concerns about zoonotic risk. Collectively, this study provides the first molecular evidence of PIV5 infection in sika deer, expanding the known host spectrum, highlighting their possible role in viral ecological circulation, and underscores the need for enhanced surveillance to assess its zoonotic potential.