High Rates of Detection of Clade 2.3.4.4 Highly Pathogenic Avian Influenza H5 Viruses in Wild Birds in the Pacific Northwest During the Winter of 2014-15.
In 2014, clade 2.3.4.4 H5N8 highly pathogenic avian influenza (HPAI) viruses spread across the Republic of Korea and ultimately were reported in China, Japan, Russia, and Europe. Mortality associated with a reassortant HPAI H5N2 virus was detected in poultry farms in western Canada at the end of November. The same strain (with identical genetic structure) was then detected in free-living wild birds that had died prior to December 8, 2014, of unrelated causes in Whatcom County, Washington, U. S. A., in an area contiguous with the index Canadian location. A gyrfalcon (Falco rusticolus) that had hunted and fed on an American wigeon (Anas americana) on December 6, 2014, in the same area, and died 2 days later, tested positive for the Eurasian-origin HPAI H5N8. Subsequently, an active surveillance program using hunter-harvested waterfowl in Washington and Oregon detected 10 HPAI H5 viruses, of three different subtypes (four H5N2, three H5N8, and three H5N1) with four segments in common (HA, PB2, NP, and MA). In addition, a mortality-based passive surveillance program detected 18 HPAI (14 H5N2 and four H5N8) cases from Idaho, Kansas, Oregon, Minnesota, Montana, Washington, and Wisconsin. Comparatively, mortality-based passive surveillance appears to have detected these HPAI infections at a higher rate than active surveillance during the period following initial introduction into the United States.
A U.S. Geological Survey National Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711.
Hon S
HS
Ip
A U.S. Geological Survey National Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711.
Robert J
RJ
Dusek
A U.S. Geological Survey National Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711.
Barbara
B
Bodenstein
B U.S. Department of Agriculture National Veterinary Services Laboratories, 1920 Dayton Avenue, Ames, IA 50010.
Mia Kim
MK
Torchetti
C Washington Department of Fish and Wildlife, 2315 N. Discovery Place, Olympia, WA 99216.
Paul
P
DeBruyn
C Washington Department of Fish and Wildlife, 2315 N. Discovery Place, Olympia, WA 99216.
Kristin G
KG
Mansfield
D U.S. Department of Agriculture Animal and Plant Health Inspection Service Wildlife Services National Wildlife Research Center, 4101 LaPorte Avenue, Fort Collins, CO 80521.
Thomas
T
DeLiberto
A U.S. Geological Survey National Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711.
Jonathan M
JM
Sleeman
D000818:Animals; D000835:Animals, Wild / Q000821:virology*; D001717:Birds / Q000821:virology*; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D053125:Influenza A Virus, H5N2 Subtype / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity / Q000502:physiology; D000071225:Influenza A Virus, H5N8 Subtype / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity / Q000502:physiology; D005585:Influenza in Birds / Q000453:epidemiology / Q000821:virology*; D015205:Northwestern United States / Q000453:epidemiology; D010802:Phylogeny; D014774:Virulence
H5Nx; HPAIV; avian influenza; intercontinental transmission; migratory birds; surveillance strategy; wild