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Phylodynamics and dispersal of hRSV entails its permanence in the general population in between yearly outbreaks in children

Grant number: 13/12571-2
Support type:Regular Research Grants - Publications - Scientific article
Duration: July 01, 2013 - December 31, 2013
Field of knowledge:Biological Sciences - Microbiology
Principal Investigator:Paolo Marinho de Andrade Zanotto
Grantee:Paolo Marinho de Andrade Zanotto
Home Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Background: Human respiratory syncytial virus (HRSV) is one of the major etiologic agents of respiratory tract infectionsamong children worldwide.Methodology/Principal Findings: Here through a comprehensive analysis of the two major HRSV groups A and B (n = 1983)which comprise of several genotypes, we present a complex pattern of population dynamics of HRSV over a time period of50 years (1956-2006). Circulation pattern of HRSV revealed a series of expansions and fluctuations of co-circulating lineageswith a predominance of HRSVA. Positively selected amino acid substitutions of the G glycoprotein occurred uponpopulation growth of GB3 with a 60-nucleotide insertion (GB3 Insert), while other genotypes acquired substitutions uponboth population growth and decrease, thus possibly reflecting a role for immune selected epitopes in linkage to the tracedsubstitution sites that may have important relevance for vaccine design. Analysis evidenced the co-circulation andpredominance of distinct HRSV genotypes in Brazil and suggested a year-round presence of the virus. In Brazil, GA2 and GA5were the main culprits of HRSV outbreaks until recently, when the GB3 Insert became highly prevalent. Using Bayesianmethods, we determined the dispersal patterns of genotypes through several inferred migratory routes.Conclusions/Significance: Genotypes spread across continents and between neighboring areas. Crucially, genotypes alsoremained at any given region for extended periods, independent of seasonal outbreaks possibly maintained by re-infectingthe general population. (AU)