ON1 Genotype Research Articles

A multi-center study on Molecular Epidemiology of Human Respiratory Syncytial Virus from Children with Acute Lower Respiratory Tract Infections in the Mainland of China between 2015 and 2019.

Human respiratory syncytial virus (RSV) is a major pathogen of acute lower respiratory tract infection among young children. To investigate the prevalence and genetic characteristics of RSV in China, we performed a molecular epidemiological study during 2015–2019. A total of 964 RSV-positive specimens were identified from 5529 enrolled patients during a multi-center study. RSV subgroup A (RSV-A) was the predominant subgroup during this research period except in 2016. Totally, 535 sequences of the second hypervariable region (HVR-2) of the G gene were obtained. Combined with 182 Chinese sequences from GenBank, phylogenetic trees showed that 521 RSV-A sequences fell in genotypes ON1 (512), NA1 (6) and GA5 (3), respectively; while 196 RSV-B sequences fell in BA9 (193) and SAB4 (3). ON1 and BA9 were the only genotypes after December 2015. Genotypes ON1 and BA9 can be separated into 10 and 7 lineages, respectively. The HVR-2 of genotype ON1 had six amino acid changes with a frequency more than 10%, while two substitutions H258Q and H266L were co-occurrences. The HVR-2 of genotype BA9 had nine amino acid substitutions with a frequency more than 10%, while the sequences with T290I and T312I were all from 2018 to 2019. One N-glycosylation site at 237 was identified among ON1 sequences, while two N-glycosylation sites (296 and 310) were identified in the 60-nucleotide duplication region of BA9. To conclusion, ON1 and BA9 were the predominant genotypes in China during 2015–2019. For the genotypes ON1 and BA9, the G gene exhibited relatively high diversity and evolved continuously.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12250-021-00430-7.

Genotype and genetic characteristics of human respiratory syncytial virus circulating in Quanzhou, 2018-2019

Objective: To study the prevalence and genetic characteristics of human respiratory syncytial virus (HRSV) in Quanzhou city, from 2018 to 2019. Methods: A total of 141 throat swabs were collected from children patients of lower respiratory tract infection in Quanzhou children Hospital, Fujian Province from November 2018 to May 2019. RT-PCR was used to amplify the 3 'end of G gene HRSV. Sequencer 5.0 and MEGA5.05 softwares were used for sequence editing, phylogenetic tree construction and genotyping analysis. Results: Twenty-five samples were positive for HRSV. Seventeen samples succeeded to obtain the target gene, including 13 of HRSVA and 4 of HRSVB. Two genotypes were identified: ON1 genotype (13 samples, HRSVA) and BA9 genotype (4 samples, HRSVB). Five strains of ON1 genotype sequences were clustered with the ON1 sequences prevalent in Beijing, Changchun and Zhejiang from 2012 to 2015 (cluster1); one strain (FJ19-02) was clustered with the sequences of ON1 genotype circulating in many regions of China from 2012 to 2015 (cluster2); Seven strains were clustered independently (cluster FJ). FJ18-02, FJ19-14 and FJ19-15 of HRSVB were clustered with the BA9 genotype sequences prevalent in Changchun, Jilin Province in 2015, while FJ19-13 was closely related to the BA9 genotype sequences prevalent in Guangzhou and Zhejiang Province in 2013. Both the ON1 and BA9 genotypes showed variations of nucleotide and amino acid in 72 and 60 insertion segments. Amino acid mutation (H266L) only occurred among the sequence of cluster-FJ, and the mutations of H261Q and Q265L only appeared in strain FJ19-13. Conclusion: BA9 and ON1 genotypes were prevalent in Quanzhou city, from 2018 to 2019. Cluster-FJ was a newly discovered independent transmission chain, which may continue to circulate in local Quanzhou area.

Evolutionary dynamics of group A and B respiratory syncytial virus in China, 2009-2018.

Respiratory syncytial virus (RSV) is a major cause of acute respiratory tract infections in children and is a public health threat globally. To investigate the spatiotemporal dynamics of RSV evolution, we performed systematic phylogenetic analysis using all available sequences from the GenBank database, together with sequences from Shanghai, China. Both RSV-A and RSV-B appear to have originated in North America, with an inferred origin time of 1954.0 (1938.7-1967.6) and 1969.7 (1962.6-1975.5), respectively. BA-like strains of RSV-B, with a 60-nt insertion, and the ON1 strain of RSV-A, with a 72-nt insertion, emerged in 1997.6 (1996.2-1998.6) and 2010.1 (2009.1-2010.3), respectively. Since their origin, both genotypes have gradually replaced the former circulating genotypes to become the dominant strain. The population dynamic of RSV-A showed a seasonal epidemic pattern with obvious expansion in the periods of 2006-2007, 2010-2011, 2011-2012, and 2013-2014. Thirty fixed amino acid substitutions were identified during the divergence of NA4 from GA1 genotypes of RSV-A, and 13 were found during the divergence of SAB4 from GB1 of RSV-B. Importantly, ongoing evolution has occurred since the emergence of ON1, including four amino acid substitutions (I208L, E232G, T253K, and P314L). RSV-A genotypes GA5, NA4, NA1, and ON1 and RSV-B genotypes CB1, SAB4, BA-C, BA10, BA7, and BA9 were co-circulating in China from 2005 to 2015. In particular, RSV-A genotype ON1 was first detected in China in 2011, and it completely replaced GA2 to become the predominant strain after 2016. These data provide important insights into the evolution and epidemiology of RSV.

Genetic diversity and evolutionary dynamics of respiratory syncytial virus over eleven consecutive years of surveillance in Senegal.

• Phylogenetic analysis showed that there were four genotypes of HRSV-A and two genotypes of HRSV-B, with a predominance of ON1 and BA9. • The evolutionary rate of genotype ON1 was similar to that of the BA9 genotype (5.16 × 10 −3 subs/site/yr). • The rapid increase of effective population size in early 2013 was coincided with the first appearance of the ON1. • The amino acid substitutions under positive selection pressure P274L in HRSV-A and P219L in HRSV-B were found significant by all four selection models.

Molecular epidemiology of Respiratory Syncytial Virus in children in sub‐Saharan Africa

This study investigated the molecular epidemiology of respiratory syncytial virus (RSV) among febrile children with acute respiratory tract infection in Ghana, Gabon, Tanzania and Burkina Faso between 2014-2017 as well as the evolution and diversification of RSV strains from other sub-Saharan countries. Pharyngeal swabs were collected at four study sites (Agogo, Ghana: n=490; Lambaréné, Gabon: n=182; Mbeya, Tanzania: n=293; Nouna, Burkina Faso: n=115) and analysed for RSV and other respiratory viruses using rtPCR. For RSV positive samples, sequence analysis of the second hypervariable region of the G-gene was performed. A dataset of RSV strains from sub-Saharan Africa (2011-2017) currently available in GenBank was compiled. Phylogenetic analysis was conducted to identify the diversity of circulating RSV genotypes. In total, 46 samples tested RSV positive (Ghana n=31 (6.3%), Gabon n=4 (2.2%), Tanzania n=9 (3.1%), Burkina Faso n=2 (1.7%)). The most common RSV co-infection was with rhinovirus. All RSV-A strains clustered with genotype ON1 strains with a 72-nucleotide duplication and all RSV-B strains belonged to genotype BAIX. Phylogenetic analysis of amino acid sequences from sub-Saharan Africa revealed the diversification into 11 different ON1 and 22 different BAIX lineages and differentiation of ON1 and BAIX strains into potential new sub-genotypes, provisionally named ON1-NGR, BAIX-KEN1, BAIX-KEN2 and BAIX-KEN3. The study contributes to an improved understanding of the molecular epidemiology of RSV infection in sub-Saharan Africa. It provides the first phylogenetic data for RSV from Tanzania, Gabon and Burkina Faso and combines it with RSV strains from all other sub-Saharan countries currently available in GenBank.

Molecular epidemiology of respiratory syncytial virus in children in sub-Saharan Africa.

This study investigated the molecular epidemiology of respiratory syncytial virus (RSV) among febrile children with acute respiratory tract infection in Ghana, Gabon, Tanzania and Burkina Faso between 2014 and 2017 as well as the evolution and diversification of RSV strains from other sub-Saharan countries. Pharyngeal swabs were collected at four study sites (Agogo, Ghana: n=490; Lambaréné, Gabon: n=182; Mbeya, Tanzania: n=293; Nouna, Burkina Faso: n=115) and analysed for RSV and other respiratory viruses using rtPCR. For RSV-positive samples, sequence analysis of the second hypervariable region of the G gene was performed. A dataset of RSV strains from sub-Saharan Africa (2011-2017) currently available in GenBank was compiled. Phylogenetic analysis was conducted to identify the diversity of circulating RSV genotypes. In total, 46 samples were tested RSV positive (Ghana n=31 (6.3%), Gabon n=4 (2.2%), Tanzania n=9 (3.1%) and Burkina Faso n=2 (1.7%)). The most common RSV co-infection was with rhinovirus. All RSV A strains clustered with genotype ON1 strains with a 72-nucleotide duplication and all RSV B strains belonged to genotype BAIX. Phylogenetic analysis of amino acid sequences from sub-Saharan Africa revealed the diversification into 11 different ON1 and 22 different BAIX lineages and differentiation of ON1 and BAIX strains into potential new sub-genotypes, provisionally named ON1-NGR, BAIX-KEN1, BAIX-KEN2 and BAIX-KEN3. The study contributes to an improved understanding of the molecular epidemiology of RSV infection in sub-Saharan Africa. It provides the first phylogenetic data for RSV from Tanzania, Gabon and Burkina Faso and combines it with RSV strains from all other sub-Saharan countries currently available in GenBank.

For which infants with viral bronchiolitis could it be deemed appropriate to use albuterol, at least on a therapeutic trial basis?

Although there is increasing evidence showing that infants with viral bronchiolitis exhibit a high degree of heterogeneity, a core uncertainty shared by many clinicians is with regard to understanding which patients are most likely to benefit from bronchodilators such as albuterol. Based on our review, we concluded that older infants with rhinovirus (RV) bronchiolitis, especially those with a nasopharyngeal microbiome dominated by Haemophilus influenzae; those affected during nonpeak months or during non-respiratory syncytial virus (RSV) predominant months; those with wheezing at presentation; those with clinical characteristics such as atopic dermatitis or a family history of asthma in a first-degree relative; and those infants infected with RSV genotypes ON1 and BA, have the greatest likelihood of benefiting from albuterol. Presently, this patient profile could serve as the basis for rational albuterol administration in patients with viral bronchiolitis, at least on a therapeutic trial basis, and it could also be the starting point for future targeted randomized clinical trials (RCTs) on the use of albuterol among a subset of infants with bronchiolitis.

Human Respiratory Syncytial Virus Detected in Mountain Gorilla Respiratory Outbreaks

Respiratory illness (RI) accounts for a large proportion of mortalities in mountain gorillas (Gorilla beringei beringei), and fatal outbreaks, including disease caused by human metapneumovirus (HMPV) infections, have heightened concern about the risk of human pathogen transmission to this endangered species, which is not only critically important to the biodiversity of its ecosystem but also to the economies of the surrounding human communities. Our goal was to conduct a molecular epidemiologic study to detect the presence of HRSV and HMPV in fecal samples from wild human-habituated free-ranging mountain gorillas in Rwanda and to evaluate the role of these viruses in RI outbreaks. Fecal samples were collected from gorillas with clinical signs of RI between June 2012 and February 2013 and tested by real-time and conventional polymerase chain reaction (PCR) assays; comparison fecal samples were obtained from gorillas without clinical signs of RI sampled during the 2010 Virunga gorilla population census. PCR assays detected HMPV and HRSV first in spiked samples; subsequently, HRSV-A, the worldwide-circulating ON1 genotype, was detected in 12 of 20 mountain gorilla fecal samples collected from gorillas with RI during outbreaks, but not in samples from animals without respiratory illness. Our findings confirmed that pathogenic human respiratory viruses are transmitted to gorillas and that they are repeatedly introduced into mountain gorilla populations from people, attesting to the need for stringent biosecurity measures for the protection of gorilla health.

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.

Genetic Characterization of G Protein in Respiratory Syncytial Virus ON-1 Genotype in Tehran

Aim: We investigated the genetic characterization of the respiratory syncytial virus (RSV) ON-1 genotypes and their different lineages based on the G gene among children <2 years of age presenting with acute respiratory tract infections in Tehran, Iran. Materials & methods: A phylogenetic tree from the Iranian samples and ON-1 strains of various parts of the world were constructed. The amino acid composition of the RSV G protein of the ON-1 genotype was mapped. Results: Human RSV ON-1 genotypes from the Iranian samples clustered in three lineages. The most common amino acid substitutions were as follows: X218Q, I240S, L289P, Y304H and L310P. Conclusion: Continuing molecular epidemiological surveys in other regions of Iran will provide deeper insight into the nature of this replacement of the dominant RSV genotype from GA2 to ON-1 in Iran.

Predominance of ON1 and BA9 genotypes of respiratory syncytial virus (RSV) in Bulgaria, 2016-2018.

The objectives of this study were to investigate the prevalence of respiratory syncytial virus (RSV) infections in Bulgaria, to characterize the genetic diversity of the RSV strains, and to perform amino acid sequence analysis of the RSV G protein. Clinical, epidemiological data and nasopharyngeal swabs were prospectively collected from children aged less than 5 years presenting with acute respiratory infections from October 2016 to September 2018. Real-time polymerase chain reaction for 12 respiratory viruses, and sequencing, phylogenetic, and amino acid analyses of the RSV G gene/protein were performed. Of the 875 children examined, 645 (73.7%) were positive for at least one viral respiratory pathogen. RSV was the most commonly detected virus (26.2%), followed by rhinoviruses (15%), influenza A (H3N2) (9.7%), adenoviruses (9%), bocaviruses (7.2%), human metapneumovirus (6.1%), parainfluenza viruses 1/2/3 (5.8%), influenza type B (5.5%), and A(H1N1)pdm09 (3.4%). The detection rate for RSV varied across two winter seasons (36.7% vs 20.3%). RSV-B cases outnumbered those of the RSV-A throughout the study period. RSV was the most common virus detected in patients with bronchiolitis (45.1%) and pneumonia (24%). Phylogenetic analysis indicated that all the sequenced RSV-A strains belonged to the ON1 genotype and the RSV-B strains were classified as BA9 genotype. Amino acid substitutions at 15 and 22 positions of the HVR-2 were identified compared with the ON1 and BA prototype strains,respectively. This study revealed the leading role of RSV as a causative agent of serious respiratory illnesses in early childhood, year-on-year fluctuations in RSV incidence, the dominance of RSV-B, and relatively low genetic diversity in the circulating RSV strains.

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.

Genetic diversity and molecular epidemiology of respiratory syncytial virus circulated in Antananarivo, Madagascar, from 2011 to 2017: Predominance of ON1 and BA9 genotypes.

Respiratory syncytial virus is the main cause of acute respiratory infections leading to a considerable morbidity and mortality among under-5 years children. A comprehensive scheme of RSV virus evolution is of great value in implementing effective universal RSV vaccine. We investigated the clinical spectrum and molecular characteristics of detected RSV over a period of seven years (January 2011 to June 2017) in Antananarivo, the capital city of Madagascar. 671 nasopharyngeal samples taken from children aged less than 5 years suffered from ARI were screened for RSV by real-time PCR. Clinical data were retrieved from case report forms. Genotype identification was performed by reverse-transcription PCR and sequencing of the second hyper variable region (HVR2) of the G glycoprotein. Amongst samples tested, 292 (43.5 %) were found positive for RSV. RSV A predominated during the study period which accounted for 62.3 % (182/292) of positive samples while RSV B represented 37.0 % (108/292). Phylogenetic analyses identified NA1 and ON1 genotypes among RSV A. Though NA1 widespread from 2011 to 2013, ON1 became prevalent during the following years. Among RSV B, THB, CB1 and BA9 genotypes were detected. A co-circulation of THB and CB1 strains occurred during the 2011 season that was substituted by the BA9 from 2012. Malagasy ON1 strains carried some characteristic amino acid substitutions that distinguish them from the worldwide ON1 strains. By analyzing clinical spectrum, ON1 and BA genotypes seemed to prevail in mild infections compared to NA1. Results obtained here will have its implication in predicting temporal evolution of RSV at the local level. Considering the insularity of the country, information obtained should help in comparative analysis with global RSV strains to optimize vaccine efficacy.

Disease severity of respiratory syncytial virus (RSV) infection correlate to a novel set of five amino acid substitutions in the RSV attachment glycoprotein (G) in China

Human respiratory syncytial virus (RSV) is one of the major viruses of acute respiratory tract disease among infants and young children. We performed molecular epidemiology analysis of RSV among inpatient children in Guangzhou, China. Phylogenetic and Bayesian analysis showed that genotype ON1 was the only subgroup A virus in this study. Interestingly, the majority of Guangzhou ON1 strains formed a well-supported cluster, and these strains shared a novel set of five amino acid substitutions that never illustrated before. Furthermore, the degree of disease severity was assessed using a severity scoring system. The patients carrying the novel RSV A strain were associated with milder respiratory symptoms compared to other RSV A positives. In conclusion, a specific set of five amino acid substitutions was found in China and further analysis showed that disease severity was associated with these alterations. These findings will provide valuable information for the pathogenic mechanism and vaccine development of RSV.

Molecular epidemiology of respiratory syncytial virus for 28 consecutive seasons (1990-2018) and genetic variability of the duplication region in the G gene of genotypes ON1 and BA in South Korea

We investigated the molecular epidemiology of respiratory syncytial virus (RSV) isolated from children during 28 consecutive seasons (1990-2018) and the genetic variability of the duplication region of RSV genotypes ON1 and BA in South Korea. RSV was identified using culture-based methods in Hep-2 cells and was grouped as RSV-A or RSV-B by an immunofluorescence assay. The second hypervariable region of the G gene was sequenced for genotyping. The nucleotide and deduced amino acid sequences of the duplication region of RSV ON1 and BA were analyzed. A total of 670 RSV-A and 233 RSV-B isolates were obtained. For RSV-A, the NA1 genotype predominated during the 2004/2005-2011/2012 seasons. The ON1 genotype was first detected in 2011 and has since replaced all other genotypes. For RSV-B, the GB3 genotype predominated during the 1999/2000-2005/2006 seasons, but the BA genotype also replaced all other genotypes of RSV-B after the first season in which it was isolated (2005/2006). In ON1 and BA genotype RSV strains, novel sequence types of the duplication region of the G gene were identified in 50-95% and 33-80% of the isolates, respectively, in each season. The ON1 and BA9 genotypes are responsible for the current epidemics of RSV infection in South Korea. The sequences in the duplication region of the G gene have evolved continuously and might be sufficient for the identification of specific strains of the RSV-A ON1 and RSV-B BA genotypes.

Epidemiology and molecular biology of respiratory syncytial virus among hospitalized children in Guangzhou from 2013 to 2017

Objective: To understand the genetic variation and epidemiological characteristics of human respiratory syncytial virus (HRSV) in Guangzhou. Methods: Nasopharyngeal swabs specimens were collected from 0-6 year old children hospitalized with acute respiratory infection, then HRSV was tested and genotyped by RT-PCR. Phylogenetic tree was bulit using MEGA 6.0 software. NetNGlyc 1.0 server was used to predict the potential N-linked glycosylation sites. Results: A total of 1 225 nasopharyngeal specimens were collected, including 783 males and 442 females. The median (P(25), P(75)) age was 8 (3, 24) months. Among the 209 HRSV-positive cases (17.06%), 117 cases (55.98%) were HRSV-A and 92 cases (44.02%) were HRSV-B. The two distinct subgroups (HRSV-A and HRSV-B) alternately played dominant role to cause HRSV infection and exchange almost once every two years. The HRSV prevalence rate decreased with age. The HRSV-positive rate among children under 2 years old was 18.83% (196 cases), accounting for 93.78% of the total positive cases. There were 32 HRSV positive cases co-infected with at least one respiratory virus, with the co-infection rate of 15.31%. Phylogenetic tree analysis of the second hypervariable region (HVR2) of the G protein classified the HRSV-A specimens into ON1 (n=62) and NA1 (n=2) genotypes while all HRSV-B specimens belonged to BA genotype (n=53). The HVR2 of the G protein varied in using stop condon, amino acid substitutions, glycosylation sites. Conclusion: Children under 2 years old were the high risk population of HRSV infection in Guangzhou. ON1 genotype turned into a primary genetype of the HRSV-A subgroup while BA genotype dominated the HRSV-B subgroup. A greater diversification of amino acid substitutions, and some deletion and insertion of glycosylation sites embodied the polymorphism of G protein as main protective antigen.

Novel Variants of Respiratory Syncytial Virus A ON1 Associated With Increased Clinical Severity of Bronchiolitis.

A study of respiratory syncytial virus-A (RSV A) genotype ON1 genetic variability and clinical severity in infants hospitalized with bronchiolitis over 6 epidemic seasons (2012-2013 to 2017-2018) was carried out. From prospectively enrolled term infants hospitalized for bronchiolitis, samples positive for RSV A ON1 (N = 139) were sequenced in the second half of the G gene. Patients' clinical data were obtained from medical files and each infant was assigned a clinical severity score. ANOVA comparison and adjusted multinomial logistic regression were used to evaluate clinical severity score and clinical parameters. The phylogenetic analysis of 54 strains showed 3 distinct clades; sequences in the last 2 seasons differed from previous seasons. The most divergent and numerous cluster of 2017-2018 strains was characterized by a novel pattern of amino acid changes, some in antigenic sites. Several amino acid changes altered predicted glycosylation sites, with acquisition of around 10 new O-glycosylation sites. Clinical severity of bronchiolitis increased in 2016-2017 and 2017-2018 and changed according to the epidemic seasons only. Amino acid changes in the hypervariable part of G protein may have altered functions and/or changed its immunogenicity, leading to an impact on disease severity.

Circulating Respiratory Syncytial Virus Genotypes and Genetic Variability of the G Gene during 2017 and 2018/2019 Seasonal Epidemics Isolated from Children with Lower Respiratory Tract Infections in Daejeon, Korea

BackgroundRespiratory syncytial virus (RSV) is a major pathogen causing respiratory tract infections in infants and young children. The aim of this study was to confirm the genetic evolution of RSV causing respiratory infections in children at Daejeon in Korea, through G gene analysis of RSV-A and RSV-B strains that were prevalent from 2017 to 2019.MethodsPediatric patients admitted for lower respiratory tract infections at The Catholic University of Korea Daejeon St. Mary's Hospital in the 2017 and 2018/2019 RSV seasonal epidemics, who had RSV detected via multiplex polymerase chain reaction (PCR) were included. The nucleic acid containing RSV-RNA isolated from each of the patients' nasal discharge during standard multiplex PCR testing was stored. The G gene was sequenced and phylogenetic analysis was performed using MEGA X program and the genotype was confirmed.ResultsA total of 155 specimens including 49 specimens from 2017 and 106 specimens from 2018-2019 were tested. The genotype was confirmed in 18 specimens (RSV-A:RSV-B = 4:14) from 2017 and 8 specimens (RSV-A:RSV-B = 7:1) from 2018/2019. In the phylogenetic analysis, all RSV-A type showed ON1 genotype and RSV-B showed BA9 genotype.ConclusionRSV-B belonging to BA9 in 2017, and RSV-A belonging to ON1 genotype in 2018/2019 was the most prevalent circulating genotypes during the two RSV seasons in Daejeon, Korea.

Evolutionary analysis of the ON1 genotype of subtype a respiratory syncytial virus in Riyadh during 2008–16

Respiratory syncytial virus is a leading cause of acute respiratory tract infection (ARI) in children worldwide. Limited information is available on molecular epidemiology of respiratory syncytial virus (RSV) from Saudi Arabia. An attempt was made to identify and characterize RSV strains in nasopharyngeal aspirates collected from hospitalized symptomatic ARI pediatric patients with <5 years of age from Riyadh, Saudi Arabia during 2016. All the samples (n = 100) were tested for RSV by real time PCR. The RSV strains were characterized by sequencing of the second hypervariable region of G protein gene. The study sequences along with the previously reported strains from Saudi Arabia were assessed for mutational, glycosylation, phylogenetic, selection pressure and entropy analyses. Fifty percent of the nasopharyngeal aspirates were positive for RSV. The RSVA (72%) predominated as compared to RSVB (24%) during the study. The study RSVA strains (n = 29) clustered into NA1 and ON1 genotypes whereas all the RSVB sequences (n = 5) were in BA genotype by phylogenetic analysis. Interestingly, 97% of RSVA sequences (n =28) clustered into ON1 genotype with 72 bp duplication in the G protein gene. Numerous mutations, variable N-/O-glycosylation sites and purifying selections were observed in the ON1 genotype. Positive selection with high entropy value was observed for three codons in ON1 (247, 262 and 274 amino acids) indicating higher probability of variations at these positions. Our study shows the progressive emergence and predominance of the ON1 genotype in Riyadh, Saudi Arabia during 2008–16. ON1 genotype almost replaced the previously circulating RSVA strains in this region during this period. Contribution of host genetic and immune factors towards disease severity of the ON1 genotype needs to be investigated in future studies. RSV surveillance in future elaborate investigations are needed in this region to understand its disease burden, evolutionary trajectory and circulation dynamics warranting steps towards vaccine development.

Virus isolation and genotype identification of human respiratory syncytial virus in Guizhou Province, China

To investigate the genetic variation and molecular epidemiology characteristics of Human Respiratory Syncytial Virus (HRSV) in Guizhou Province, nasopharyngeal aspirates were collected from patients with acute respiratory infection (ARI) in Guizhou Provincial People's Hospital, from December 2017 to March 2018, and inoculated to Hep-2 cells to isolate HRSV. Cells that showed cytopathic effect (CPE) were then confirmed by indirect immunofluorescence assay and reverse transcription. The sequence of the PCR products was determined for HRSV isolates, and the genetic variation was analyzed. Out of 196 nasopharyngeal aspirate samples, HRSV were isolated in 39. The second hypervariable region at the 3′ terminal of glycoprotein gene (HVR2) sequence analysis showed that subgroup A was dominant. Seventy-nine percent of the isolates belonged to subgroup A, ON1 genotype, and 21 % belonged to subgroup B, BA9 genotype, which indicates that the dominant HRSV circulating in Guizhou Province was subgroup A, genotype ON1, co-circulating with a less prevalent subgroup B, genotype BA9.