Estudio prospectivo sobre los patrones genéticos y correlaciones filogenéticas de las cepas gripales aisladas en las Islas Baleares

The aim of this study is to analyze the genetic and antigenic characteristics of influenza virus strains isolated in our regional zone in the 2006-2007 epidemical season. Automatized methods were used for the processes of isolation, typing, amplification and genetic secuence analysis of viral strains. The results were analyzed by the Clustal W informatic program and the phylogenetic trees were developed by the methods of neighbor-joining and bootstrap. We studied 20 viral strains, 2 influenza A (H1N1), 14 influenza A (H3N2) and 4 influenza B. The H1N1 strains were genetically identified as belonging to the vaccine clade 1 (A/New Caledonian/20/99-like). In the rest of Spain the predominance was influenza strains belonging to clade 2 (A/Solomon Islands/3/06-like). In the H3N2 influenza strains we detected 2 genetical clusters. The predominat (57%) was not genetically related to vaccine strain (A/Wisconsin/67/05), starting the seasonal antigenic drift. Of influenza B strains, we detected one strain related to the vaccine strain (Victoria clade) and the others were phylogenetically related to the Yamagata clade. We detected an antigenic and genetic mistmatch between the isolated B strains and the vaccine strain. These genetic studies are very important to know and evaluated the strains that co-circulate in every influenza season. The detection of an important mistmath (antigenic drift) could determine the modification of the influenza vaccine composition and the need to re-vaccinated all the population with an aditional dosis. La importancia del conocimiento de las características genéticas y antigénicas de las cepas gripales que afectan a una determinada comunidad en una determinada temporada gripal, es la base sobre la que se ha realizado este estudio sobre cepas aisladas en la temporada 2006-2007. Los procesos de aislamiento, tipificación, amplificación y secuenciación genética se han realizado por métodos automatizados. Los datos se analizaron mediante el programa Clustal W y los árboles filogenéticos se realizaron mediante la técnica de neighbor-joining y bootstrap. De las 20 cepas estudiadas, 2 eran influenza A (H1N1), 14 influenza A (H3N2) y 4 influenza B. Las cepas H1N1 fueron identificadas genéticamente como pertenecientres al linaje 1 (A/New Caledonian/20/99-like) vacunal. Aunque la mayoría de cepas aisladas en el resto del país pertenecían al linaje 2 (A/Solomon Islands/3/06-like). En las cepas H3N2 se han obtenido 2 agrupaciones genéticas distintas