North American Avian Flu Study

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Highly pathogenic avian influenza (HPAI) H5 viruses of Eurasian origin continue to circulate and evolve in North American wild birds, according to a study by the U.S. Geological Survey and U.S. Department of Agriculture. Published in the journal Genome Announcements, the report summarizes a genetic analysis of a mixed-origin HPAI H5N1 avian flu virus.

The virus was discovered in a green-winged teal in Washington State that was sampled at the end of 2014. It is a mixed-origin virus containing genes from the Eurasian HPAI H5N8 and genes from North American low pathogenic avian influenza from wild birds. This H5N1 virus is different from the well-known Asian H5N1 HPAI virus that emerged in 1996.

The publication follows a recent article describing the introduction of Eurasian HPAI H5N8 into North America at the end of 2014 and the detection of a different mixed-origin virus (HPAI H5N2) in wild birds.

In March 2015, the HPAI H5N2 virus was detected in commercial turkey flocks in Minnesota, Missouri and Arkansas, in a backyard flock of mixed poultry in Kansas and in a wild bird in Wyoming.

The term ‘highly pathogenic’ refers to the ability of an avian influenza virus strain to produce disease in chickens. The population-level impact of these viruses on free-living wild bird species is currently unknown.

As with the parental Eurasian H5N8 virus, no human infections with this H5N1 virus have been detected. However, similar viruses have infected people in other countries, according to the Centers for Disease Control and Prevention.

More information on avian influenza is available at the USGS National Wildlife Health Center website or the USDA Animal and Plant Health Inspection Service avian influenza page.

source: U.S. Geological Survey