Caracterización epidemiológica y evolutiva del virus de influenza A en cerdos de Chile
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Fecha
2016
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Profesor/a Guía
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Idioma
es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
El virus de Influenza A (VIA) circula endemicamente en poblaciones de cerdos y
humanos, además de otras especies en la naturaleza, presentando una preocupación
constante a la Salud Pública y a la industria de producción animal a nivel mundial.
Estudios de vigilancia de estos agentes infecciosos ha sido una preocupación creciente
para la industria de cerdos en Chile, la cual se encuentra dentro de las mayores
exportadoras de carne de cerdo en el mundo. Chile tiene barreras ecológicas fuertes, y
una alta rigurosidad respecto al traspaso de animales vivos por las fronteras. Sin
embargo, desde el año 2009, una circulación constante de VIA ha sido observada en
cerdos. A pesar de esto, hay una capacidad de diagnóstico y vigilancia muy limitada en
cuanto a la detección de estos virus en el país. En este trabajo estandarizamos
herramientas de diagnóstico y subtipificación para identificar y caracterizar la diversidad
de los VIA porcinos y su prevalencia en granjas locales de cerdo. También analizamos
la prevalencia viral y las características genómicas de los VIA encontrados en estos
sitios de producción. Estudios serológicos mostraron que hay una alta prevalencia de
varias cepas de VIA, con una tasa de infección general de un 56,9% en diferentes
poblaciones de cerdos. Al genotipificar hemos identificado la co-circulación de tres
subtipos de VIA, teniendo hasta dos cepas circulantes por sitio. Nuestros datos indican
que la mayoría de los cerdos son susceptibles a la infección entre los 70 y 110 días de
edad (cerdos en engorda). Cuando obtuvimos muestras de este grupo, aislamos 57
virus de distintos sitios de producción, en comparación a los 3 que habíamos aislado de
muestras previas. Secuenciación y análisis de genoma completo de 26 de estos virus
reveló múltiples cepas co-circulando en cerdos, además de una cepa recombinante.
Adicionalmente, los análisis filogenéticos sugieren un evento de transmisión de un VIA
humano a hospedero porcino. Esto es particularmente evidente desde el surgimiento
del virus pandémico H1N1 del 2009, el cual ha sido introducido en múltiples ocasiones
a la población de cerdos chilenos. En resumen, este trabajo ha permitido el primer
estudio comprehensivo de diversidad y evolución de los virus de VIA porcinos en Chile,
y coloca en perspectiva la amenaza que estos pueden causar no sólo a cerdos, si no
que a la salud humana también.
Influenza A Virus (IAV) circulates endemically in swine and human populations, and other species in nature, presenting a constant concern to Public Health and animal production industries worldwide. Surveillance studies of these infectious agents has been of increasing concern for the swine industry in Chile, which currently is one of the largest exporter countries of swine meat in the world. Chile has strong ecological barriers and high stringency regarding livestock crossing across its borders. Nevertheless, since 2009, constant circulation of IAV has been observed in pigs. However, there is limited diagnostic and surveillance capacity for detection of these viruses in the country. We standardized diagnostic and subtyping tools to identify and characterize the diversity of swine IAV (SIV) and its prevalence in local pig farms. We also analysed viral prevalence and genomic characteristics of IAV found at these production sites. Serological studies showed that there is high prevalence of several IAV strains, with an overall infection rate of 56.9% in different swine populations. Genotyping identified the co-circulation of three IAV subtypes, with up to two circulating strains per site. Our data indicates that most pigs are susceptible to infection at 70 to 110 days of age (fattening pigs). When we sampled this group, we isolated 57 viruses from diverse production sites, in comparison to the 3 we isolated from previous samples. Full-genome sequencing and analysis of the full genome of 26 of these viruses revealed multiple strains co-circulating in swine, as well as a reassortant strain. Furthermore, transmission of human IAV to swine host is strongly suggested by our phylogenetic analyses. This is particularly evident since the emergence of the 2009 H1N1 pandemic virus, which has been introduced in multiple occasions into the swine population in Chile. Overall, this work allows the first comprehensive study of diversity and evolution of swine IAV in Chile, and puts into perspective the threat that it may cause not only to swine, but to human health alike.
Influenza A Virus (IAV) circulates endemically in swine and human populations, and other species in nature, presenting a constant concern to Public Health and animal production industries worldwide. Surveillance studies of these infectious agents has been of increasing concern for the swine industry in Chile, which currently is one of the largest exporter countries of swine meat in the world. Chile has strong ecological barriers and high stringency regarding livestock crossing across its borders. Nevertheless, since 2009, constant circulation of IAV has been observed in pigs. However, there is limited diagnostic and surveillance capacity for detection of these viruses in the country. We standardized diagnostic and subtyping tools to identify and characterize the diversity of swine IAV (SIV) and its prevalence in local pig farms. We also analysed viral prevalence and genomic characteristics of IAV found at these production sites. Serological studies showed that there is high prevalence of several IAV strains, with an overall infection rate of 56.9% in different swine populations. Genotyping identified the co-circulation of three IAV subtypes, with up to two circulating strains per site. Our data indicates that most pigs are susceptible to infection at 70 to 110 days of age (fattening pigs). When we sampled this group, we isolated 57 viruses from diverse production sites, in comparison to the 3 we isolated from previous samples. Full-genome sequencing and analysis of the full genome of 26 of these viruses revealed multiple strains co-circulating in swine, as well as a reassortant strain. Furthermore, transmission of human IAV to swine host is strongly suggested by our phylogenetic analyses. This is particularly evident since the emergence of the 2009 H1N1 pandemic virus, which has been introduced in multiple occasions into the swine population in Chile. Overall, this work allows the first comprehensive study of diversity and evolution of swine IAV in Chile, and puts into perspective the threat that it may cause not only to swine, but to human health alike.
Notas
Tesis (Magíster en Biotecnología)
Palabras clave
Gripe Porcina, Chile