Genomic Characterization and Putative Recombination Signals of Ostrich-Associated Parvovirus in South China

Since 2020, a disease characterized by paralysis and diarrhea has affected ostriches in southern China, resulting in significant economic losses for ostrich farms. Initial analyses of clinical samples from affected birds indicated the presence of a parvovirus as a potential causative agent. This study aimed to identify and characterize the involved pathogenic parvovirus, analyze its genetic features, determine its phylogenetic relationship with known parvovirus strains, and investigate its role in the observed clinical symptoms. We collected 15 clinical samples ((including sciatic nerve, spleen, kidney, and other visceral organs) from 15 affected ostriches and performed gross pathological and histopathological examinations. Whole-genome sequencing of the detected ostrich parvovirus (OsPV) was conducted, followed by phylogenetic, genetic distance, and recombination analyses. Ostrich parvovirus (OsPV) was detected in the collected clinical samples, and viral genomic DNA was identified across multiple tissues, indicating broad tissue distribution. Phylogenetic analysis revealed that OsPV forms a unique branch within the goose parvovirus (GPV) group and is closely related to Chinese GPV strains, particularly the DY16 strain. Notably, the identified virus possessed two 14 bp deletions in its inverted terminal repeats. Furthermore, the virus (designated GX-2020) was identified as carrying recombination signals derived from the SYG61v and B strains of GPV. Recombination among classical GPV strains likely facilitated the emergence of OsPV and may point to possible cross-species transmission or host-range expansion of GPV. This study offers new insights into the evolution, molecular biology, and host adaptation of parvoviruses in China.