Sequence analysis of the G gene of hRSVA ON1 genotype from Egyptian children with acute respiratory tract infections

Dominance of the ON1 Genotype of RSV-A and BA9 Genotype of RSV-B in Respiratory Cases from Jeddah, Saudi Arabia

Human respiratory syncytial virus (HRSV) is a main cause of hospital admission for lower respiratory tract infection. In previous studies from Saudi Arabia, higher prevalence of the NA1 genotype in group A was observed from Riyadh and Taif. This study recruited respiratory cases from Jeddah during January to December, 2017. RSV represented 13.4% in the recruited cases with 64% of them belonging to group A and 36% to group B. All group A cases in this study were ON1 type characterized by duplication of 72 nucleotides, 24 amino acids in the C-terminal in the second hypervariable region of the G gene. In addition, for group B all of the cases were clustered under BA9, which had uniquely characterized as duplication of 60 nucleotides in the G protein. Our sequences showed similarity with earlier sequences from Saudi Arabia, Kuwait, Thailand, South Africa, Spain, the USA and Cyprus. Some amino acid substitutions in the investigated sequences would cause a change in potential O-glycosylation and N-glycosylation profiles from prototype ON1. The predominance of the ON1 and BA9 genotype of RSV-A in Jeddah compared to previous Saudi studies showing predominance of the NA1 genotype for group A. This difference in genotype prevalence could be due to fast spread of the ON1 genotype worldwide or due to the flux of travelers through Jeddah during hajj/umrah compared to Riyadh and Taif. This shift in genotype distribution requires continuous surveillance for genetic characterization of circulating respiratory infections including RSV. These findings may contribute to the understanding of RSV evolution and to the potential development of a vaccine against RSV.

Molecular characterization of respiratory syncytial virus circulating in Tunisia between 2015 and 2018

Introduction. Respiratory syncytial virus (RSV) is the most frequently identified viral agent in children with lower respiratory tract infection (LRTI). No data are available to date regarding RSV genotypes circulating in Tunisia.Aim. The aim of the present study was to investigate the genetic variability of the glycoprotein G gene in Tunisian RSV strains.Methodology. Nasopharyngeal aspirates were collected from infants hospitalized for LRTI in five Tunisian hospitals. All specimens were screened for RSV by a direct immunofluorescence assay (DIFA). To molecularly characterize Tunisian RSV strains, a phylogenetic analysis was conducted. Randomly selected positive samples were subjected to reverse transcription PCR amplifying the second hyper-variable region (HVR2) of the G gene.Results. Among a total of 1417 samples collected between 2015 and 2018, 394 (27.8 %) were positive for RSV by DIFA. Analysis of 61 randomly selected RSV strains revealed that group A RSV (78.7 %) predominated during the period of study as compared to group B RSV (21.3 %). The phylogenetic analysis showed that two genotypes of RSV-A were co-circulating: the ON1 genotype with a 72-nt duplication in HVR2 of the G gene was predominant (98.0 % of RSV-A strains), while one RSV-A strain clustered with the NA1 genotype (2.0 %). Concerning Tunisian group B RSV strains, all sequences contained a 60-nt insertion in HVR2 and a clustered BA10 genotype.Conclusion. These data suggest that RSV-A genotype ON1 and RSV-B genotype BA10, both with duplications in the G gene, were widely circulating in the Central coastal region of Tunisia between 2015 and 2018.

Systematic Review of the Respiratory Syncytial Virus (RSV) Prevalence, Genotype Distribution, and Seasonality in Children from the Middle East and North Africa (MENA) Region

Respiratory syncytial virus (RSV) is one of the most common viruses to infect children worldwide and is the leading cause of lower respiratory tract illness (LRI) in infants. This study aimed to conduct a systematic review by collecting and reviewing all the published knowledge about the epidemiology of RSV in the Middle East and North Africa (MENA) region. Therefore, we systematically searched four databases; Embase, Medline, Scopus, and Cochrane databases from 2001 to 2019 to collect all the information related to the RSV prevalence, genotype distribution, and seasonality in children in MENA region. Our search strategy identified 598 studies, of which 83 met our inclusion criteria, which cover the past 19 years (2000–2019). Odds ratio (OR) and confidence interval (CI) were calculated to measure the association between RSV prevalence, gender, and age distribution. An overall prevalence of 24.4% (n = 17,106/69,981) of respiratory infections was recorded for RSV. The highest RSV prevalence was reported in Jordan (64%, during 2006–2007) and Israel (56%, 2005–2006). RSV A subgroup was more prevalent (62.9%; OR = 2.9, 95%CI = 2.64–3.13) than RSV B. RSV was most prevalent in children who were less than 12 months old (68.6%; OR = 4.7, 95%CI = 2.6–8.6) and was higher in males (59.6%; OR = 2.17, 95%CI = 1.2–3.8) than in female infants. Finally, the highest prevalence was recorded during winter seasons in all countries, except for Pakistan. RSV prevalence in the MENA region is comparable with the global one (24.4% vs. 22%). This first comprehensive report about RSV prevalence in the MENA region and our data should be important to guide vaccine introduction decisions and future evaluation.

Preliminary functional and phylogeographic analyses of the 72 nucleotide duplication region in the emerging human respiratory syncytial virus ON1 strain attachment glycoprotein gene

The emerging human respiratory syncytial virus (hRSV) ON1 strain, which is characterized by a 72-nt duplication in the attachment glycoprotein (G) gene, has replaced other prevailing global genotypes since its discovery in 2012. In this study, we used the pseudotype lentiviral system to directly address the effect of the duplication on hRSV infection. In addition, representative 199 ON1 sequences selected from 2599 ON1 sequences that were downloaded from GenBank were used to perform Bayesian skyline and phylogeographic analyses. Our results showed that lentiviral pseudoparticles mimicked the key functions of the G-protein on hRSV cell entry. Further, we showed that deletion of the G-protein duplication decreased the efficiency of pLV infection. The mean substitution rate of the second mucin-like highly variable region for the ON1 G-protein gene was 2.14 × 10^-3 (95 % HPD: 1.23 × 10^-3, 3.08 × 10^-3) nucleotide substitutions per site per year. Phylogeographic analyses showed that the ON1 isolates might originate from Europe at the time of MRCA (i.e., the most recent common ancestors), which dated back to 1998.3 (95 % HPD: 1989.2, 2005.2). These preliminary findings revealed the enhanced attachment function of the duplication region in the ON1 G gene and highlighted the importance of ongoing surveillance of ON1 to better understand the molecular epidemiology of hRSV.