Analysis of circulating respiratory syncytial virus A strains in Shanghai, China identified a new and increasingly prevalent lineage within the dominant ON1 genotype
Xue Zhao, Chun Wang, Hui Jiang, Hong Zhang, Fanghao Fang, Min Chen, Zhengan Yuan, Zheng Teng, Jing Liu, Xi Zhang
Abstract
Respiratory syncytial virus A (RSV-A) is one of the commonest pathogens causing acute respiratory tract infections in infants and children globally. The currently dominant circulating genotype of RSV-A, ON1, was first detected in Shanghai, China in 2011, but little data are available regarding its subsequent circulation and clinical impact here. In this work, we analyzed RSV-A infection in a cohort of patients hospitalized for acute respiratory infections in Shanghai Children's Hospital, and RSV-A was detected in ~10% of these cases. RSV-A G gene sequencing revealed that all successfully sequenced strains belonged to ON1 genotype, but in phylogenetic analysis, the majority of these sequences formed a clade separate from the four previously established lineages within ON1. The new lineage, denoted ON1-5, was supported by phylogenetic analyses using additional G gene sequences from RSV-A strains isolated in Shanghai and elsewhere. ON1-5 first appeared in 2015 in China and the Netherlands, and has since spread to multiple continents and gained dominance in Asia. In our cohort, ON1-5 was not associated with markedly different clinical presentations compared to other ON1 lineages. ON1-5 strains are characterized by four amino acid variations in the two mucin-like regions of G protein, and one variation (N178G) within the highly conserved CCD domain that is involved in receptor binding. These data highlight the continuous evolution of RSV-A, and suggest the possibility of the virus acquiring variations in domains traditionally considered to be conserved for fitness gain.