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 ... -  《-》

Molecular epidemiology of human respiratory syncytial virus over three consecutive seasons in Latvia.

Lower respiratory tract infections caused by the human respiratory syncytial virus (HRSV) represent an immense burden of the disease, especially in young children. This study aimed to investigate the evolutionary history of HRSV strains isolated in the Children's Clinical University Hospital (Riga, Latvia) over three consecutive HRSV seasons. Of 207 samples from children hospitalized with lower respiratory tract infections, 88 (42.5%) tested positive for HRSV by RT-PCR. The seasonal activity started and peaked later than the average for the Northern hemisphere. Patients with HRSV lower respiratory tract infection were significantly younger than patients not infected with HRSV. HRSV-A viruses predominated for two consecutive seasons and were followed by an HRSV-B dominant season. Phylogenetic analysis based on glycoprotein G gene partial sequences revealed that viruses of both groups belonged to the worldwide dominant genotypes NA1 (HRSV-A) and BA-IV (HRSV-B). High diversity of this gene was driven only partially by selection pressure, as only two positively selected sites were identified in each group. Two of the HRSV-A isolates in this study contained a 72-nt duplication in the C-terminal end of the G gene (genotype ON1) that was first described in Canada in the 2010-2011 season. Initial spatial and temporal dynamics of this novel genotype were reconstructed by discrete phylogeographic analysis. Fifteen years after acquiring comparable 60-nt duplication in the G gene, genotype BA lineages have replaced all other HRSV-B strains. However, the population size of genotype ON1 plateaued soon and even decreased slightly before the beginning of the 2012-2013 season.

Balmaks R ，Ribakova I ，Gardovska D ，Kazaks A ... -  《-》

Molecular epidemiology and molecular characterization of respiratory syncytial viruses at a tertiary care university hospital in Catalonia (Spain) during the 2013-2014 season.

Human respiratory syncytial virus (HRSV) is the main cause of lower respiratory tract infections among infants and young children. The molecular epidemiology and characterization of HRSV strains detected at a Spanish tertiary hospital during the 2013-2014 season is reported. Phylogenetic analysis and molecular characterization of HRSV laboratory-confirmed respiratory samples were performed, based on coding sequences of G and F proteins. HRSV infection was laboratory-confirmed in respiratory samples from 320 patients of which 223 (70%) were less than 2 years of age and none undergoing Palivizumab treatment. HRSV was detected at varying levels throughout the season with a maximum rate in the week 52/2013, right before the beginning of the influenza epidemic. Whilst both HRSV groups were found co-circulating, HRSV-B group clearly predominated. The phylogenetic analyses from 139 HVR-2 sequences revealed that most characterized strains belonged to ON1 and BA9 genotypes. Three different phylogenetic subgroups could be distinguished within these genotypes. In addition, three strains (out of the 52 randomly selected) were carrying amino acid substitutions in the epitope A of the F protein, one of them previously related to Palivizumab resistance. The results of the present study highlight the importance of a continuous HRSV surveillance to monitor not only the introduction of new genotypes on circulation but also the emergence of viral variants with new genetic characteristics that can affect the antigenicity features and the susceptibility to the only current prophylaxis treatment and also for the future development of HRSV vaccines.

Gimferrer L ，Campins M ，Codina MG ，Martín Mdel C ，Fuentes F ，Esperalba J ，Bruguera A ，Vilca LM ，Armadans L ，Pumarola T ，Antón A ... -  《-》

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 ... -  《-》

Prevalence of respiratory syncytial virus group B genotype BA-IV strains among children with acute respiratory tract infection in Kolkata, Eastern India.

Agrawal AS ，Sarkar M ，Ghosh S ，Chawla-Sarkar M ，Chakraborty N ，Basak M ，Naik TN ... -  《-》