Respiratory syncytial virus genotypes NA1, ON1, and BA9 are prevalent in Thailand, 2012-2015.

Ilada Thongpan,Yong Poovorawan,John Mauleekoonphairoj,Sumeth Korkong,Sompong Vongpunsawad,Preeyaporn Vichiwattana,Rujipat Wasitthankasem

doi:10.7717/peerj.3970

Abstract

Respiratory syncytial virus (RSV) causes acute lower respiratory tract infection in infants and young children worldwide. To investigate the RSV burden in Thailand over four consecutive years (January 2012 to December 2015), we screened 3,306 samples obtained from children ≤5 years old with acute respiratory tract infection using semi-nested reverse-transcription polymerase chain reaction (RT-PCR). In all, 8.4% (277/3,306) of the specimens tested positive for RSV, most of which appeared in the rainy months of July to November. We then genotyped RSV by sequencing the G glycoprotein gene and performed phylogenetic analysis to determine the RSV antigenic subgroup. The majority (57.4%, 159/277) of the RSV belonged to subgroup A (RSV-A), of which NA1 genotype was the most common in 2012 while ON1 genotype became prevalent the following year. Among samples tested positive for RSV-B subgroup B (RSV-B) (42.6%, 118/277), most were genotype BA9 (92.6%, 87/94) with some BA10 and BA-C. Predicted amino acid sequence from the partial G region showed highly conserved N-linked glycosylation site at residue N237 among all RSV-A ON1 strains (68/68), and at residues N296 (86/87) and N310 (87/87) among RSV-B BA9 strains. Positive selection of key residues combined with notable sequence variations on the G gene contributed to the continued circulation of this rapidly evolving virus.

Highlights

Human respiratory syncytial virus (RSV) is a major cause of severe respiratory infections in infants and young children (Nair et al, 2010)
RSV was identified in 8.4% (277/3,306) of all samples tested, of which 57.4% (159/277) were RSV belonged to subgroup A (RSV-A) and 42.6% (118/277) were RSV-B (Table 1)
Cyclical pattern was reflected by the predominance of RSV-A in 2012, RSV-B in 2013 and 2014, and the subsequent return of RSV-A predominance in 2015

Summary

Introduction

Human respiratory syncytial virus (RSV) is a major cause of severe respiratory infections in infants and young children (Nair et al, 2010). RSV is a member of the newly assigned genus Orthopneumovirus in the family Pneumoviridae (Afonso et al, 2016). It has a single-stranded negative-sense RNA genome of approximately 15.2 kb, which encodes 11 viral proteins (Collins, Fearns & Graham, 2013). The viral envelope glycoproteins G and F are important for the receptor attachment and viral fusion with the target cell, respectively. Both surface glycoproteins can induce the host immune response (Wagner et al, 1989)

Methods

Results

Conclusion