Abstract
Southwest Alaska serves as an important staging area for migratory waterfowl that breed in Alaska and East Asia. Since 2011, approximately 1,000 samples originating from hunter-harvested waterfowl and environmental feces have been collected annually in and around Izembek National Wildlife Refuge in this region to assess the occurrence and spread of avian influenza viruses. Genetic analysis of avian influenza viruses from wild birds inhabiting this region has repeatedly identified intercontinental viral dispersal events and revealed viruses composed of gene segments of both North American and Eurasian lineages. In late 2014 and late 2021, H5 subtype highly pathogenic avian influenza (HPAI) viruses were introduced into North America, though prevalence among wild birds inhabiting southwest Alaska differed between HPAI introduction events. The occurrence, dissemination, and evolution of HPAI virus genotypes in this region may have been influenced by the genetic and antigenic diversity of low pathogenicity avian influenza (LPAI) viruses present among migratory birds and vice versa. We therefore analyzed trends in LPAI and HPAI virus occurrence, diversity, and evolution in this region through time and relative to HPAI introductions. Results may help elucidate how the changing ecology of HPAI viruses among wild birds has affected viral prevalence, diversity, and evolution over time at one of the most consistently sampled active surveillance sites for avian influenza in North America.
Co-Author(s)
Christina Ahlstrom, USGS Alaska Science Center
Laura Scott, USGS Alaska Science Center
Rebecca Poulson, University of Georgia
David Stallknecht, University of Georgia
Andrew Ramey, USGS Alaska Science Center
Abstract Category
Notable outbreaks, field and molecular epidemiology, and surveillance in wild birds