title: Molecular evolution of respiratory syncytial virus subgroup A genotype NA1 and ON1 attachment glycoprotein (G) gene in central Vietnam.
abstract: We performed molecular evolutionary analyses of the G gene C-terminal 3rd hypervariable region of RSV-A genotypes NA1 and ON1 strains from the paediatric acute respiratory infection patients in central Vietnam during the 2010-2012 study period. Time-scaled phylogenetic analyses were performed using Bayesian Markov Chain Monte Carlo (MCMC) method, and pairwise distances (p-distances) were calculated. Bayesian Skyline Plot (BSP) was constructed to analyze the time-trend relative genetic diversity of central Vietnam RSV-A strains. We also estimated the N-glycosylation sites within G gene hypervariable region. Amino acid substitutions under positive and negative selection pressure were examined using Conservative Single Likelihood Ancestor Counting (SLAC), Fixed Effects Likelihood (FEL), Internal Fixed Effects Likelihood (IFEL) and Mixed Effects Model for Episodic Diversifying Selection (MEME) models. The majority of central Vietnam ON1 strains detected in 2012 were classified into lineage 1 with few positively selected substitutions. As for the Vietnamese NA1 strains, four lineages were circulating during the study period with a few positive selection sites. Shifting patterns of the predominantly circulating NA1 lineage were observed in each year during the investigation period. Median p-distance of central Vietnam NA1 strains was wider (p-distance=0.028) than that of ON1 (p-distance=0.012). The molecular evolutionary rate of central Vietnam ON1 strains was estimated to be 2.55×10-2(substitutions/site/year) and was faster than NA1 (7.12×10-3(substitutions/site/year)). Interestingly, the evolutionary rates of both genotypes ON1 and NA1 strains from central Vietnam were faster than the global strains respectively. Furthermore, the shifts of N-glycosylation pattern within the G gene 3rd hypervariable region of Vietnamese NA1 strains were observed in each year. BSP analysis indicated the rapid growth of RSV-A effective population size in early 2012. These results suggested that the molecular evolution of RSV-A G gene detected in central Vietnam was fast with unique evolutionary dynamics.
authors.affiliation: Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan; Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Yoshihara
authors.affiliation: Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan; National Institute of Hygiene and Epidemiology, Hanoi, Vietnam.
authors.forename: Minh Nhat
authors.initials: MN
authors.lastname: Le
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Musashimurayama, Tokyo 208-0011, Japan.
authors.forename: Koo
authors.initials: K
authors.lastname: Nagasawa
authors.affiliation: Gunma Prefectural Institute of Public Health and Environmental Sciences, Maebashi, Gunma 371-0052, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsukagoshi
authors.affiliation: National Institute of Hygiene and Epidemiology, Hanoi, Vietnam.
authors.forename: Hien Anh
authors.initials: HA
authors.lastname: Nguyen
authors.affiliation: Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Toizumi
authors.affiliation: Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523, Japan; Department of Paediatrics, Nagasaki University Hospital, Nagasaki 852-8102, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Moriuchi
authors.affiliation: Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hashizume
authors.affiliation: Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan.
authors.forename: Koya
authors.initials: K
authors.lastname: Ariyoshi
authors.affiliation: National Institute of Hygiene and Epidemiology, Hanoi, Vietnam.
authors.forename: Duc Anh
authors.initials: DA
authors.lastname: Dang
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Musashimurayama, Tokyo 208-0011, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kimura
authors.affiliation: Department of Paediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan. Electronic address: lmyoshi@nagasaki-u.ac.jp.
authors.forename: Lay-Myint
authors.initials: LM
authors.lastname: Yoshida
mesh_terms: D001499:Bayes Theorem; D002675:Child, Preschool; D015331:Cohort Studies; D019143:Evolution, Molecular; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D017720:Molecular Epidemiology; D010802:Phylogeny; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology / Q000821:virology*; D018113:Respiratory Syncytial Virus, Human / Q000145:classification / Q000235:genetics*; D014744:Vietnam / Q000453:epidemiology; D014759:Viral Envelope Proteins / Q000235:genetics
chemical_list: D014759:Viral Envelope Proteins
keywords: ARI; Molecular evolution; ON1; Paediatric infectious diseases; RSV; Vietnam