Genetic diversity of human respiratory syncytial virus in children with acute respiratory infections in Chennai, South India

ABSTRACT

Introduction: Human respiratory syncytial virus (HRSV) an RNA virus belonging to Pneumoviridae family, is an important cause of acute respiratory infections (ARIs) in young children. HRSV circulates as two subgroups A and B, which are further categorised into several genotypes. New genotypes may replace existing ones over successive epidemic seasons and multiple genotypes may cocirculate in the same community rendering it important to monitor them at the molecular level. The present study assessed the circulating genotypes of HRSV in Chennai. Materials and Methods: Two hundred and sixty-seven children with ARI were recruited during the study from April 2016 to March 2018 for detecting HRSV A and B by real-time reverse transcription-polymerase chain reaction. Phylogeny and selection pressure analysis were done. Results: Fifty-seven of the 267 samples (21.3%) were positive for HRSV, of which 7.1% and 14.2% were HRSV A and B, respectively, indicating that HRSV B was the major subgroup circulating in Chennai. Peak activity of HRSV was observed during the monsoon and winter months. Phylogenetic analysis of 2nd hypervariable region (HVR) of attachment glycoprotein gene (G gene) revealed that the HRSV A strains belonged to ON1 and HRSV B strains belonged to BA9 genotypes. Several unique amino acid substitutions were observed among the study strains. The Shannon entropy plot revealed that the HRSV A strains from our study have a high potential for amino acid substitutions in the 2nd HVR of G gene. Conclusion: This study underlines the genetic diversity of HRSV and emphasises the need for continued molecular surveillance for infection management and prevention strategies.