Genetic characteristics of human bocavirus in children with acute respiratory tract infections during 2023 in Beijing, China.

Human bocavirus (HBoV) is an emerging pathogen associated with pediatric respiratory and gastrointestinal infections, yet its genetic diversity remains understudied. The aberrant global resurgence of other respiratory viruses after the COVID-19 pandemic has raised concerns regarding significant evolutionary shifts in viral genetic profiles. Accordingly, this study characterized HBoV isolates that circulated in Beijing during 2023 by analyzing 1,442 pediatric respiratory samples associated with acute respiratory tract infections. Among 43 HBoV-positive cases with a 2.98% detection rate, 11 complete genomes were sequenced and classified as HBoV1 through phylogenetic analysis. Amino acid substitutions in VP1, including the prevalent N474S mutation (95.3% frequency in GenBank), were predicted via structural modeling to alter hydrogen-bonding networks, potentially enhancing viral stability. Entropy analysis confirmed the high variability of VP1, whereas selective pressure analysis revealed conserved sites under purifying selection in the NP1 and VP1 proteins. Notably, the S79N substitution in NP1 introduced a putatively N-glycosylation site while a putatively O-glycosylation site was lost in four isolates, may suggesting functional implications. No recombination events were detected. These findings provide critical insights into the molecular evolution of HBoV1 and inform future research on antiviral strategies.