Alternate circulation and genetic variation of human respiratory syncytial virus genotypes in Chengdu, West China, 2009-2014.

Human respiratory syncytial virus (HRSV) is a major pathogen that causes worldwide seasonal epidemic disease in infants due to its genetic variations. However, published information on the molecular epidemiology of HRSV was never reported particularly in Chengdu of West China. During five consecutive seasons (from 2009 to 2014), 433 (23.7%) of 1827 samples from hospitalized patients were identified as HRSV positive. Epidemiological characteristics of HRSV revealed that subtype A viruses (62.7%) prevailed in the first three epidemic seasons and faded in the next two seasons, while subtype B viruses (37.3%) kept circulating in five epidemic periods. According to the phylogenetic analysis of glycoprotein (G) gene, five HRSV genotypes NA1, ON1, BA9, BA-C, and CB1 were found in Chengdu. The predominant circulating genotype changed from NA1 in the period of 2010-2012 to BA9 of 2013-2014. The newly emerging ON1 was first reported in West China in October 2013. The early genotypes BA-C and CB1 were replaced by the prevailing BA9 after the third epidemic peak. Genetic mutations in glycosylation sites of G protein were found in HRSV variants, suggesting the virus is able to escape the immune recognition and attack. This study elucidated the local HRSV epidemic was associated with the alternate circulation of multiple genotypes and with the change of glycosylation sites of G protein. J. Med. Virol. 89:32-40, 2017. © 2016 Wiley Periodicals, Inc.

Hu P ，Zheng T ，Chen J ，Zhou T ，Chen Y ，Xu X ，Pei X ... -  《-》

Molecular characterization of human respiratory syncytial virus subtype B: a novel genotype of subtype B circulating in China.

Human respiratory syncytial virus (HRSV) is major pathogen of lower respiratory tract infections in infants and young children worldwide. There have been many studies regarding HRSV subgroup A (HRSV-A) G protein genetic variability but little information about HRSV subtype B (HRSV-B) G protein genetic diversity and molecular evolution in China. Thus, a survey of the molecular epidemiology and evolution of the G protein in China is of high importance. In this study, the circulation and genetic diversity of HRSV in Chongqing, Southwestern China, from June 2009 to May 2013, were investigated. A total of 3,167 nasopharyngeal aspirates were obtained in this study, and it was found that HRSV-B predominated in the 2009-2010 and 2012-2013 epidemic seasons. This study identified the genetic variability of the glycoprotein G gene among 102 HRSV-B strains isolated by cell culture from Chongqing nasopharyngeal aspirates, and 68 Chinese HRSV-B sequences were deposited in GenBank. Genotyping and phylogenetic analysis revealed that the HRSV-B strains were clustered into three genotypes: BA (n = 111, 65.29%), GB3 (n = 5, 2.94%), and a new GB genotype (n = 54, 31.77%) named GB5. The GB5 strains varied from other genotypes in the central conserved region and N-glycosylation sites. The estimated evolutionary rate of Chinese HRSV-B was 2.01 × 10(-3) nucleotide substitutions/site/year, which is similar to the reports from Belgium and the Netherlands with 1.95 × 10(-3) and 2.78 × 10(-3) nucleotide substitutions/site/year, respectively. This study provides data on the circulating pattern and molecular characterization of HRSV-B genotypes in China during four consecutive years and may contribute to HRSV vaccine development.

Ren L ，Xiao Q ，Zhou L ，Xia Q ，Liu E ... -  《-》

Genetic variation of human respiratory syncytial virus among children with fever and respiratory symptoms in Shanghai, China, from 2009 to 2012.

Human respiratory syncytial virus (HRSV) of genus Pneumovirus is one of the most common pathogens causing severe acute lower respiratory tract infection in infants and children. No information on the genotype distribution of HRSV is available in East China (e.g. Shanghai). From August 2009 to December 2012, 2407 nasopharyngeal swabs were collected from outpatient children with fever and respiratory symptoms in Shanghai. HRSV infection was determined using a multiplex RT-PCR assay. The second hypervariable region (HVR2) of G protein gene of HRSV was amplified and sequenced from HRSV positive samples. Genotypes were characterized by phylogenetic analyses. Of 2407 nasopharyngeal samples, 184 (7.6%) were tested as HRSV positive. From 160 positive subjects with sufficient nasopharyngeal samples, 69 HVR2 sequences were obtained by RT-PCR and sequencing. Three HRSV epidemic seasons were observed from August 2009 to December 2012, and an extreme outbreak of HRSV occurred in the 2009-2010 epidemic season. A genotype shift of predominant HRSV strains from B group in the 2009-2010 epidemic season to group A in the subsequent epidemic seasons was observed. Ten HRSV genotypes, including four group A genotypes NA1, NA3, NA4, and ON1, and six group B genotypes BA9, BA10, SAB4, CB1, BAc, and BA?, were detected in Shanghai. Seven genotypes (NA1, BA9-10, SAB4, CB1, BAc and BA?) were found in the 2009-2010 epidemic season. The co-circulation of multiple genotypes was associated with the extreme outbreak of HRSV among children with fever and respiratory symptoms in the 2009-2010 epidemic season.

Liu J ，Mu Y ，Dong W ，Yao F ，Wang L ，Yan H ，Lan K ，Zhang C ... -  《-》

Tracing the emerging genotypes of human respiratory syncytial virus in Beijing by evolution analysis of the attachment glycoprotein (G) gene.

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. 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. 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. 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.

Zhang T ，Qian Y ，Deng J ，Zhu R ，Wang F ，Sun Y ，Ding Y ，Tian R ，Zhao L ... -  《-》

A study of the genetic variability of human respiratory syncytial virus in Croatia, 2006-2008.

Human respiratory syncytial virus (HRSV) is a common etiological agent of acute lower respiratory tract disease in infants. The molecular epidemiology of HRSV in Croatia over four consecutive seasons (from 2006 to 2008) was investigated. A total of 72 HRSV samples were chosen from 696 screened cases in a pediatric clinic in Zagreb. Molecular characterization of HRSV revealed the predominance of HRSV group B viruses in the first two epidemic seasons and HRSV group A viruses in the next two seasons. According to the phylogenetic analysis, NA1 and BA9 were the predominant circulating HRSV genotypes detected during the study. Overall, 82.9% of all HRSV A strains belonged to the NA1 genotype. The HRSV B genotype BA9, detected in two consecutive seasons (2006 and 2007), was the predominant circulating HRSV B genotype, accounting for 80.6% of all HRSV B strains. This study provides data on the circulation pattern of HRSV genotypes in Croatia and their molecular characterization.

Forcic D ，Ivancic-Jelecki J ，Mlinaric-Galinovic G ，Vojnovic G ，Babic-Erceg A ，Tabain I ... -  《-》