Discovery of novel highly pathogenic avian influenza H5N1 virus in USA wild birds (January 21, 2015)
A novel H5N1-reassortant virus belonging the same group as other recently reported H5 viruses which are highly pathogenic (HPAI) to poultry has been identified from a green-winged teal (Anas carolinensis) collected from a hunter-harvest surveillance project funded by the U.S. Geological Survey. The bird was sampled in Whatcom County, Washington on December 29, 2014. This novel virus, designated EA/AM H5N1, is different from the Asian HPAI H5N1 and is a mixture of Eurasian (EA) and low pathogenic North American (AM) origin viruses.
In response to initial detections of HPAI virus in wild birds in backyard poultry in the USA and Canada, the USGS National Wildlife Health Center (NWHC) is working closely with the USDA - Wildlife Services, U.S. Fish and Wildlife Service, Washington Department of Fish and Wildlife, and other state Wildlife Departments to implement enhanced mortality and hunter-harvest surveillance in wild birds. As of mid-January, NWHC has tested oropharyngeal/cloacal swabs from over 1,200 birds originating from California, Nevada, Oregon, and Washington with the majority of collections focused in Washington. Of these samples, 167 were positive for avian influenza viruses by an initial molecular screening test (matrix RT-PCR) and 20 were positive for H5 subtypes by follow-up molecular testing. As a member of the National Animal Health Laboratory Network, NWHC sends H5-positive samples to USDA?s National Veterinary Services Laboratories (NVSL) for further characterization. On January 21 2015, NVSL confirmed identification of the EA/AM H5N1 virus as containing PB2, H5, NP, and MP RNA segments identical to the gyrfalcon H5N8 previously identified in Whatcom, County and PB1, PA, N1, and NS RNA segments from North American low-pathogenic avian influenza viruses of wild bird origin.
Additional information on this and other winter (2014/2015) wild bird surveillance results can be found at: