RESUMEN
Swine influenza A viruses (SwIV) cause significant economic losses in animal husbandry as well as instances of human disease and occasionally give rise to human pandemics, including that caused by the H1N1/2009 virus. The lack of systematic and longitudinal influenza surveillance in pigs has hampered attempts to reconstruct the origins of this pandemic. Most existing swine data were derived from opportunistic samples collected from diseased pigs in disparate geographical regions, not from prospective studies in defined locations, hence the evolutionary and transmission dynamics of SwIV are poorly understood. Here we quantify the epidemiological, genetic and antigenic dynamics of SwIV in Hong Kong using a data set of more than 650 SwIV isolates and more than 800 swine sera from 12 years of systematic surveillance in this region, supplemented with data stretching back 34 years. Intercontinental virus movement has led to reassortment and lineage replacement, creating an antigenically and genetically diverse virus population whose dynamics are quantitatively different from those previously observed for human influenza viruses. Our findings indicate that increased antigenic drift is associated with reassortment events and offer insights into the emergence of influenza viruses with epidemic potential in swine and humans.
Asunto(s)
Evolución Molecular , Subtipo H1N1 del Virus de la Influenza A/fisiología , Infecciones por Orthomyxoviridae/veterinaria , Enfermedades de los Porcinos/transmisión , Enfermedades de los Porcinos/virología , Porcinos/virología , Zoonosis/virología , Animales , Aves/virología , Femenino , Hong Kong/epidemiología , Humanos , Subtipo H1N1 del Virus de la Influenza A/clasificación , Subtipo H1N1 del Virus de la Influenza A/genética , Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Gripe Aviar/transmisión , Gripe Aviar/virología , Gripe Humana/epidemiología , Gripe Humana/transmisión , Gripe Humana/virología , Masculino , Epidemiología Molecular , Datos de Secuencia Molecular , Infecciones por Orthomyxoviridae/epidemiología , Infecciones por Orthomyxoviridae/transmisión , Infecciones por Orthomyxoviridae/virología , Filogenia , Vigilancia de la Población , Virus Reordenados/genética , Virus Reordenados/inmunología , Virus Reordenados/aislamiento & purificación , Virus Reordenados/fisiología , Porcinos/sangre , Enfermedades de los Porcinos/sangre , Enfermedades de los Porcinos/epidemiología , Zoonosis/epidemiología , Zoonosis/transmisiónRESUMEN
To study influenza viruses in pigs in Sri Lanka, we examined samples from pigs at slaughterhouses. Influenza (H3N2) and A(H1N1)pdm09 viruses were prevalent during 2004-2005 and 2009-2012, respectively. Genetic and epidemiologic analyses of human and swine influenza viruses indicated 2 events of A(H1N1)pdm09 virus spillover from humans to pigs.
Asunto(s)
Infecciones por Orthomyxoviridae/veterinaria , Infecciones del Sistema Respiratorio/veterinaria , Enfermedades de los Porcinos/virología , Mataderos , Animales , Línea Celular , Embrión de Pollo , Perros , Humanos , Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Subtipo H3N2 del Virus de la Influenza A/aislamiento & purificación , Infecciones por Orthomyxoviridae/epidemiología , Infecciones por Orthomyxoviridae/virología , Filogenia , Prevalencia , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/virología , Estudios Seroepidemiológicos , Sri Lanka/epidemiología , Sus scrofa/virología , Porcinos/virología , Enfermedades de los Porcinos/epidemiologíaRESUMEN
To assess herd immunity to swine influenza viruses, we determined antibodies in 28 paired serum samples from participants in a prospective serologic cohort study in Hong Kong who had seroconverted to pandemic (H1N1) 2009 virus. Results indicated that infection with pandemic (H1N1) 2009 broadens cross-reactive immunity to other recent subtype H1 swine viruses.