A Study of Influenza Viruses in Their Natural Reservoir in Wild Birds in Norway

The major goal of this project is to better understand the dynamics of influenza A virus infections in wild birds in Norway. At the National Veterinary Institute, in the context of the surveillance for highly pathogenic avian influenza virus H5N1, a large collection of samples is being gathered from different wild bird species. This material is of special value, both in national and international perspectives, as influenza viruses mostly replicate in juvenile birds as they congregate before migration from northern parts of Europe. Evolutionary aspects of influenza A virus in wild birds in Norway will be studied by bioinformatic approaches using genomic sequences that will be obtained from the collected influenza viruses. Variations in the functions of vi ral proteins from the different virus subtypes will be studied by assessment of the binding activities, enzymatic activities and effects on innate immune responses. By applying in trans complementation of siRNA knocked out viral gene transcripts with gene transcripts from different subtypes of virus, including human adapted influenza A viruses, studies of the intimate cross-talk between the different viral segments will be allowed. This may indicate the ease by which genetic reassortments of different gen omic segments can give rise to infectious viruses. The aim is to obtain better understanding of the virulence factors and properties related to the spread of avian influenza A virus. In addition, survival of the viral infectivity in the environment will b e studied, to assess the role of water as reservoir for different influenza A virus subtypes in the winter months in Norway.