Genetic variability of human respiratory syncytial virus in Pune, Western India
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.
Available from: Don Hayes
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ABSTRACT: Respiratory syncytial virus (RSV) is an important respiratory pathogen in infants and children worldwide. Although RSV typically causes mild upper respiratory infections, it frequently causes severe morbidity and mortality, especially in premature infants and children with other chronic diseases. Treatment of RSV is limited by a lack of effective antiviral treatments; however, ribavirin has been used in complicated cases, along with the addition of intravenous immune globulin in specific patients. Vaccination strategies for RSV prevention are heavily studied, but only palivizumab (Synagis(®)) has been approved for use in the United States in very select patient populations. Research is ongoing in developing additional vaccines, along with alternative therapies that may help prevent or decrease the severity of RSV infections in infants and children. To date, we have not seen a decrement in RSV morbidity and mortality with our current options; therefore, there is a clear need for novel RSV preventative and therapeutic strategies. In this review, we discuss the current and evolving trends in RSV treatment for infants and children.
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ABSTRACT: Human respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections in infants and children under five years of age. The novel genotype ON1 has a 72-nucleotide duplication, which is the largest duplicated genome portion of RSV. Whether the ON1 genotype will follow the pattern of the BA genotype, which has a 60-nucleotide duplication, and become the predominant RSV-A strain is a global concern. To obtain information regarding the prevalence of the ON1 genotype in Chongqing in Southwestern China, we examined the circulation pattern of RSV-A identified over four consecutive years (June 2009 to August 2013). In this study, 312 (12%) RSV-A strains were isolated from 2601 nasopharyngeal aspirates, and partial G gene was sequenced successfully in 250 isolates. Of the sequenced Chongqing RSV-A isolates, 237 (94.8%) strains were the NA1 genotype, 4 (1.6%) strains were the NA3 genotype, 4 (1.6%) strains were the NA4 genotype, 1 (0.4%) strain was the GA1 genotype, and 4 (1.6%) strains were identified as the ON1 genotype. Analysis of the distribution, phylogeny, and evolution of the ON1 strains that were collected globally until December 2013 revealed that the ON1 genotype has rapidly disseminated across the world under positive selection pressures. Future studies will determine whether this new genotype will continue to spread and become the dominant strain of RSV-A worldwide. These findings may contribute to the understanding of RSV evolution and to the potential development of a vaccine against RSV.
Available from: Christiane Prifert
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ABSTRACT: Respiratory syncytial virus (RSV) is the leading cause of hospitalization especially in young children with respiratory tract infections (RTI). Patterns of circulating RSV genotypes can provide a better understanding of the molecular epidemiology of RSV infection. We retrospectively analyzed the genetic diversity of RSV infection in hospitalized children with acute RTI admitted to University Hospital Heidelberg/Germany between October 2012 and April 2013. Nasopharyngeal aspirates (NPA) were routinely obtained in 240 children younger than 2 years of age who presented with clinical symptoms of upper or lower RTI. We analyzed NPAs via PCR and sequence analysis of the second variable region of the RSV G gene coding for the attachment glycoprotein. We obtained medical records reviewing routine clinical data. RSV was detected in 134/240 children. In RSV-positive patients the most common diagnosis was bronchitis/bronchiolitis (75.4%). The mean duration of hospitalization was longer in RSV-positive compared to RSV-negative patients (3.5 vs. 5.1 days; p<0.01). RSV-A was detected in 82.1%, RSV-B in 17.9% of all samples. Phylogenetic analysis of 112 isolates revealed that the majority of RSV-A strains (65%) belonged to the novel ON1 genotype containing a 72-nucleotide duplication. However, genotype ON1 was not associated with a more severe course of illness when taking basic clinical/laboratory parameters into account. Molecular characterization of RSV confirms the co-circulation of multiple genotypes of subtype RSV-A and RSV-B. The duplication in the G gene of genotype ON1 might have an effect on the rapid spread of this emerging RSV strain.
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