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

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.

Evolution of Human Respiratory Syncytial Virus (RSV) over Multiple Seasons in New South Wales, Australia

“…The number of samples was skewed with the majority collected in 2016, comprising 36 RSVA and 57 RSVB sequences, respectively ( Figure 1 A). Despite this limited sampling, it is evident that RSVA and RSVB co-circulated in every season, which is consistent with other molecular epidemiological studies [ 41 , 42 , 43 , 44 ]. A distinct seasonality was apparent with peaks typically occurring in the early winter period (May to July) ( Figure 1 A).…”

Epidemiology and genetic variability of respiratory syncytial virus in Portugal, 2014–2018

“…BA10 strains showed 100% homology in the HVR2 to reference strains from Thailand (KY328142,KY328145) and had the exclusive substitution E292 G, which has been observed in other studies [58,59]. Continual surveillance of amino acid changes as well as novel N-linked glycosylation sites should be performed since alterations in the antigenic characteristics of the viral surface glycoproteins may enable immune evasion leading to an evolutionary advantage [45,58]. In fact, the spread of BA genotype has been explained by the 60-nc duplication in the HVR2, which was associated with an increase of virus attachment and fitness [60].…”

“…The alignment of the predicted amino acid sequences of strains from BA9, NA1 and ON1 genotypes confirmed the relatively high genetic variability associated with the HVR2. Strains from both of subtypes showed common changes, conserved N-glycosilation sites and subtitutions leading to loss or gain of these sites that had been previously reported [11,40,41,45,46,49,50,[54][55][56][57][58][59]. Within RSV-A strains, the number of substitutions among ON1 strains was higher compared with its NA1 counterparts.…”

“…Within RSV-A strains, the number of substitutions among ON1 strains was higher compared with its NA1 counterparts. BA10 strains showed 100% homology in the HVR2 to reference strains from Thailand (KY328142,KY328145) and had the exclusive substitution E292 G, which has been observed in other studies [58,59]. Continual surveillance of amino acid changes as well as novel N-linked glycosylation sites should be performed since alterations in the antigenic characteristics of the viral surface glycoproteins may enable immune evasion leading to an evolutionary advantage [45,58].…”

Epidemiology and Phylogenetic Analysis of Viral Respiratory Infections in Vietnam

“…Similarly, patients co-infected with RSV and IAV also tended to have longer lengths of stay than those only infected with RSV or IAV. Our estimation of the percentage of RSV in Vietnam (23%) was similar to those reported among hospitalized ARI patients in several other Asia countries including China, Indonesia, Malaysia, and Thailand (ranging from 18 to 23% (Chan et al, 2002;Yoshida et al, 2010;Ohno et al, 2013;Hu et al, 2017;Thongpan et al, 2017). The percentage of IAV (11%) was similar to that in the United States and Mexico (Jain et al, 2015b).…”