Evidence of feline chaphamaparvovirus in dogs: molecular detection, genetic recombination, and tissue localization.

BACKGROUND: Feline chaphamaparvovirus (FChPV) is a parvovirus primarily identified in cats, and more recently detected in dogs—including the first confirmed canine report from China in 2023—suggesting potential cross-species transmission. However, its clinical significance and host adaptation remain unclear. This study investigated FChPV infection in dogs with respiratory and enteric diseases, assessed its genetic diversity, and determined viral localization. RESULTS: A total of 392 dogs were screened for FChPV using conventional PCR, whole-genome sequencing, and in situ hybridization (ISH). FChPV DNA was detected in 4 of 392 dogs (1.0%), with three exhibiting enteric disease and one presenting respiratory sign. Phylogenetic analysis clustered canine FChPV strains into two distinct clades, sharing 98.3–99.6% genetic similarity with feline strains. Genetic recombination event was found in one canine strain (CP003/Dog/2020), with the feline strains identified in China were served as putative major and minor parents. ISH confirmed the localization of FChPV DNA within inflammatory cells across multiple tissues, primarily in the spleen and intestines. Additional signals were also detected in the brain, though no significant pathological changes were observed. CONCLUSIONS: These findings extend previous canine reports by providing molecular and histopathological evidence of FChPV infection in dogs from Southeast Asia. The low detection rate and presence of co-infections complicate interpretation of pathogenicity. Further investigation is needed to clarify transmission dynamics, host adaptation, and clinical relevance in canine populations.