Genetic variability of human respiratory syncytial virus in Pune, Western India.
ABSTRACT Human respiratory syncytial virus (RSV) is one of the most important respiratory viruses causing acute respiratory tract infections amongst children. Based on genotyping of the attachment glycoprotein (G) gene, it is divided into two groups, RSV-A and RSV-B. Infection with one group does not confer immunity against the other and children infected with one antigenic group are more likely to be reinfected with the heterologous group. We tested 854 samples of patients with influenza like illness (ILI)/ severe respiratory illness (SARI) during the period 2009-2012 for RSV using a conventional multiplex RT-PCR and found 159 (18.61%) samples to be positive for RSV of which 130 (15.22%) were positive for RSV-B and 29 (3.39%) for RSV-A suggesting that RSV-B was the predominant group circulating in western India during the study period. Seasonal RSV outbreaks were observed in the monsoon and winter months. RSV was more prevalent amongst children in the 0-24 month age group (21.53%) in comparison to children in the 24-60 month age group (13.01%). Phylogenetic analysis using the G gene of 27 representative RSV-A positive samples revealed that all sequences belonged to the NA1 genotype. Of these, 5 sequences exhibited the novel 72 nucleotide duplication in the C-terminal of the G gene first reported from Ontario, Canada and clustered in the newly designated ON1 genotype. Also, 32 of the 33 RSV-B sequences exhibited the 60 nucleotide duplication associated with genotype BA and phylogenetic analysis showed that these sequences belonged to the genotype BA9 and BA12. We also found one RSV-B sequence belonging to genotype GB2, which has not been previously reported in India.
- SourceAvailable from: Patricia CaneJournal of General Virology 11/1997; 78 ( Pt 10):2411-8. · 3.13 Impact Factor
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ABSTRACT: Human respiratory syncytial virus (HRSV) is classified into two major groups, A and B, each of which contains multiple variants. To characterize the molecular epidemiology of HRSV strains over time, sequencing studies of a variable region of the attachment protein gene from a single community in the United States during 5 successive years were performed. Phylogenetic analysis revealed distinct clades (genotypes) that were further classified in subtypes based on > or = 96% nucleotide similarity. Five genotypes and 22 subtypes among 123 group A HRSV isolates, and four distinct genotypes and six subtypes among 81 group B HRSV isolates were identified. One to two genotypes or subtypes accounted for > or = 50% of isolates from a given year. A shift in the predominant genotype or subtype occurred each year such that no genotype or subtype predominated for more than 1 of the 5 study years. The consistency in the displacement of the predominant strain suggests that a shift, even within the same group, is advantageous to the virus. It was hypothesized that the 'novel' strain is better able to evade previously induced immunity in the population and consequently either circulates more efficiently or is more pathogenic. The yearly shift in HRSV strains may contribute to the ability of HRSV to consistently cause yearly outbreaks of HRSV disease. These results also suggest that isolates may need to be characterized as to both group and genotype to fully understand protective immunity after natural infection and efficacy studies of candidate vaccines.Journal of General Virology 10/1998; 79 ( Pt 9):2221-9. · 3.13 Impact Factor
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ABSTRACT: Respiratory syncytial (RS) viruses isolated over three epidemic periods in a children's hospital in the United States were analyzed. The viruses (n = 174) were characterized as to major antigenic group (group A or B) by a PCR-based assay. Group A RS viruses were dominant the first 2 years, followed by a year with group B dominance (ratios of group A to group B viruses for epidemic periods, 56/4 for 1993-1994, 42/3 for 1994-1995, and 19/50 for 1995-1996). Genetic variability within the groups was assessed by restriction fragment analysis of PCR products; 79 isolates were also analyzed by nucleotide sequence determination of a variable region of the glycoprotein G gene. Among the group A RS virus isolates, this G-protein variable region had amino acid differences of as great as 38%. The G-protein amino acids of the group A viruses differed by up to 31% from the G-protein amino acids of a prototype (A2) group A virus. Among the group B RS virus G proteins, amino acid differences were as great as 14%. The G-protein amino acids of the group B viruses differed by up to 27% from the G-protein amino acids of a prototype (18537) group B virus. The group A and group B RS viruses demonstrated genetic variability between years and within individual years. Phylogenetic analysis revealed that there were multiple evolutionary lineages among both the group A and group B viruses. Among the recent group B isolates, variability was less than that seen for the group A viruses. However, comparisons to prototype strains revealed that the group B RS viruses may vary more extensively than was observed over the 3 years studied in the present investigation.Journal of Clinical Microbiology 01/1999; 36(12):3552-7. · 4.07 Impact Factor