Influenza viruses in wild birds

Although people typically think of influenza viruses in terms of human health, the natural reservoir and primary hosts for these viruses are wild birds. Influenza virus genomes are segmented, with 8 individual pieces of negative-sense RNA making the full genome complement. This segmented nature of the genome facilitates rapid evolution through the generation of novel reassorted viruses when an individual host is co-infected with more than one virus. Avian influenza virus genes can be separated phylogenetically into geographic lineages (e.g. North American, South American and Eurasian). This is caused by the geographic separation of host species between regions, and there is also some further phylogenetic segregation of the virus genes by host species taxonomy. We have been characterizing influenza viruses from wild birds in Newfoundland and Labrador, with a particular focus on gulls and pelagic seabirds. Through this work we have identified a number of viruses that contain mixtures of genes from both North America and Eurasia, indicating that Newfoundland is an important location for the interaction of viruses from these two regions. These virus interactions are facilitated by bird host movements, with some of the sampled species documented to move across the Atlantic Ocean between North America and Eurasia