Tuohui Zhang1, Yuan Qian1, Jie Deng1, Runan Zhu1, Fang Wang1, Yu Sun1, Yaxin Ding1, Run Tian1, Linqing Zhao2. 1. Laboratory of Virology, Beijing Key Laboratory of Etiology of Viral Diseases in Children, Capital Institute of Pediatrics, 2 Yabao Road, Beijing 100020, China. 2. Laboratory of Virology, Beijing Key Laboratory of Etiology of Viral Diseases in Children, Capital Institute of Pediatrics, 2 Yabao Road, Beijing 100020, China. Electronic address: linqingz525@163.com.
Abstract
BACKGROUND: Emerging human respiratory syncytial virus (HRSV) genotypes, such as ON1 and BA9, are becoming the dominant genotypes prevailing worldwide. Objective To trace the emerging HRSV genotypes in Beijing. METHODS: HRSV-positive specimens as determined by direct immunofluorescence, collected from children diagnosed with bronchiolitis from July 2006 to June 2016, were typed by real-time PCR, then genotyped by phylogenetic analyses of the full attachment glycoprotein (G) gene. A Bayesian skyline plot was constructed to analyze the population dynamics for identified HRSV strains, and selective pressure was analyzed. RESULTS: The previous dominant HRSV A genotype, NA1, was replaced by ON1 in 2014. BA9 was the dominant HRSV B genotype for the duration of the study. The time to the most recent common ancestor (tMRCA) for HRSV A is since the 1943-1944 season; for the genotypes NA1 and ON1, since the 1999-2000 season and 2010-2011 season, respectively. The tMRCA for HRSV B is since the 1956-1957 season; for the genotypes BA and BA9, from the 1998-1999 season and 2005-2006 season, respectively. The mean evolutionary rate of HRSV A (3.65 × 10-3) was faster than those of HRSV B (3.11 × 10-3), and the genotypes NA1 (2.01 × 10-3) and ON1 (1.66 × 10-3). The estimated effective population size (EPS) infected by HRSV A changed significantly from 2012 to 2013, which is consistent with the detection of ON1. Most positive selection sites were concentrated in the second highly variable region (HVR2) of the G gene. CONCLUSIONS: Over the 10-year period from 2006 to 2016, the dominant genotypes in Beijing were NA1, ON1, and BA9. The HRSV strains in Beijing may have their own unique phylogenetic characteristics.
BACKGROUND: Emerging human respiratory syncytial virus (HRSV) genotypes, such as ON1 and BA9, are becoming the dominant genotypes prevailing worldwide. Objective To trace the emerging HRSV genotypes in Beijing. METHODS:HRSV-positive specimens as determined by direct immunofluorescence, collected from children diagnosed with bronchiolitis from July 2006 to June 2016, were typed by real-time PCR, then genotyped by phylogenetic analyses of the full attachment glycoprotein (G) gene. A Bayesian skyline plot was constructed to analyze the population dynamics for identified HRSV strains, and selective pressure was analyzed. RESULTS: The previous dominant HRSV A genotype, NA1, was replaced by ON1 in 2014. BA9 was the dominant HRSV B genotype for the duration of the study. The time to the most recent common ancestor (tMRCA) for HRSV A is since the 1943-1944 season; for the genotypes NA1 and ON1, since the 1999-2000 season and 2010-2011 season, respectively. The tMRCA for HRSV B is since the 1956-1957 season; for the genotypes BA and BA9, from the 1998-1999 season and 2005-2006 season, respectively. The mean evolutionary rate of HRSV A (3.65 × 10-3) was faster than those of HRSV B (3.11 × 10-3), and the genotypes NA1 (2.01 × 10-3) and ON1 (1.66 × 10-3). The estimated effective population size (EPS) infected by HRSV A changed significantly from 2012 to 2013, which is consistent with the detection of ON1. Most positive selection sites were concentrated in the second highly variable region (HVR2) of the G gene. CONCLUSIONS: Over the 10-year period from 2006 to 2016, the dominant genotypes in Beijing were NA1, ON1, and BA9. The HRSV strains in Beijing may have their own unique phylogenetic characteristics.