Assuntos
Vírus da Influenza A Subtipo H1N1 , Influenza Humana/epidemiologia , África Subsaariana/epidemiologia , Antivirais/provisão & distribuição , Argentina/epidemiologia , Austrália/epidemiologia , Humanos , Índia/epidemiologia , Vírus da Influenza A Subtipo H1N1/genética , Vacinas contra Influenza/provisão & distribuição , Influenza Humana/diagnóstico , Influenza Humana/tratamento farmacológico , Influenza Humana/virologia , Japão/epidemiologia , México/epidemiologia , Vigilância da População , Saúde Pública , Estados Unidos/epidemiologia , Vietnã/epidemiologiaRESUMO
Antigenic and genetic analysis of the hemagglutinin of approximately 13,000 human influenza A (H3N2) viruses from six continents during 2002-2007 revealed that there was continuous circulation in east and Southeast Asia (E-SE Asia) via a region-wide network of temporally overlapping epidemics and that epidemics in the temperate regions were seeded from this network each year. Seed strains generally first reached Oceania, North America, and Europe, and later South America. This evidence suggests that once A (H3N2) viruses leave E-SE Asia, they are unlikely to contribute to long-term viral evolution. If the trends observed during this period are an accurate representation of overall patterns of spread, then the antigenic characteristics of A (H3N2) viruses outside E-SE Asia may be forecast each year based on surveillance within E-SE Asia, with consequent improvements to vaccine strain selection.