Intercontinental reassortment and genomic variation of low pathogenic avian influenza viruses isolated from northern pintails (Anas acuta) in Alaska: Examining the evidence through space and time

Abstract

Migration and population genetic data for northern pintails (Anas acuta) and phylogenetic analysis of low pathogenic avian influenza (LPAI) viruses from this host in Alaska suggest that northern pintails are involved in ongoing intercontinental transmission of avian influenza. Here, we further refine this conclusion through phylogenetic analyses which demonstrate that detection of foreign lineage gene segments is spatially dependent and consistent through time. Our results show detection of foreign lineage gene segments to be most likely at sample locations on the Alaska Peninsula and least likely along the Southern Alaska Coast. Asian lineages detected at four gene segments persisted across years, suggesting maintenance in avian hosts that migrate to Alaska each year from Asia or in hosts that remain in Alaska throughout the year. Alternatively, live viruses may persist in the environment and re-infect birds in subsequent seasons.

Introduction of Eurasian-Origin Influenza A(H8N4) Virus into North America by Migratory Birds

“…Therefore, phylogenetic analyses provided support for Eurasian ancestry of this genomic constellation. We inferred our results to provide evidence for the introduction of this foreign-origin H8N4 virus into North America by migratory birds given previous support for intercontinental viral dispersal derived through genetic characterization of avian influenza A viruses originating from western Alaska ( 1 – 3 , 5 ), the intercontinental migratory tendencies of northern pintails ( 6 , 7 ) and other species inhabiting Izembek NWR at the time of sampling ( 8 ), the paucity of domestic poultry in this region, and the proximity of Izembek NWR to East Asia.…”

“…Research of and surveillance for influenza A viruses in wild birds inhabiting western Alaska have consistently provided support for the exchange of viruses between East Asia and North America via Beringia ( 1 , 2 ). Sampling of wild birds inhabiting Izembek National Wildlife Refuge (NWR) and surrounding areas in Alaska (≈55°N, 163°W) conducted during 2011–2015 has been used in recent research to identify the dispersal of influenza A(H9N2) viruses among China, South Korea, and Alaska ( 3 ); provide inference about the evolutionary pathways of economically important foreign-origin poultry pathogens introduced into North America ( 4 ); and identify sampling efficiencies for optimizing the detection of evidence for intercontinental virus exchange ( 5 ).…”

Accumulation and Inactivation of Avian Influenza Virus by the Filter-Feeding Invertebrate Daphnia magna

“…For all experiments, we used the wildbird-origin low-pathogenicity AIV strain A/northern pintail/Alaska/ 44340-268/2007(H3N8) that was isolated from a cloacal swab of a northern pintail duck (Anas acuta) captured on the Yukon-Kuskokwim Delta, AK, in 2007 and initially cultured in allantoic fluid at the USGS National Wildlife Health Center, Madison, WI (30). AIV was propagated in MDCK cells (American Type Culture Collection, Manassas, VA) in 75-cm 2 flasks containing Eagle's minimal essential medium, 10% fetal bovine serum, and tosylsulfonyl phenylalanyl chloromethyl ketone (TPCK)-treated trypsin (1 g ml Ϫ1 ).…”

The Recent Establishment of North American H10 Lineage Influenza Viruses in Australian Wild Waterfowl and the Evolution of Australian Avian Influenza Viruses

“…Intercontinental virus transmission and reassortment between Eurasian and North American influenza virus lineages have been periodically observed (15,16); however, their establishment in the introduced region has rarely been recorded (6). Intercontinental gene flow between divergent lineages can lead to long-lasting effects on the local avian influenza virus population structure, with eventual extinction of the endemic lineages (6).…”