USDA Confirms Highly Pathogenic H5N2 Avian Influenza in Wild Birds in Kentucky

 

CDC considers the risk to people from these HPAI H5 infections in wild birds, backyard flocks and commercial poultry, to be low

 

WASHINGTON, April 28, 2015 -- The United States Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed the presence of highly pathogenic H5N2 avian influenza (HPAI) in two wild birds, a goose and a duck, in McCracken County, Kentucky.  These birds were found within the Mississippi flyway where this strain of avian influenza has previously been identified. CDC considers the risk to people from these HPAI H5 infections in wild birds, backyard flocks and commercial poultry, to be low.  No human infections with the virus have been detected at this time.

The samples, taken from dead birds, were tested by the Southeastern Cooperative Wildlife Disease Study at the University of Georgia and confirmed by USDA’s National Veterinary Services Laboratories (NVSL) in Ames, Iowa.  NVSL is the only internationally recognized AI reference laboratory in the United States.  The United States has the strongest AI surveillance program in the world, and USDA is working with its partners to actively look for the disease in commercial poultry operations, live bird markets and in migratory wild bird populations.

USDA will include the confirmation information in routine updates to the World Organization for Animal Health (OIE).  OIE trade guidelines call on countries to base trade restrictions on sound science and specifically state that countries should not impose trade restrictions based on findings of HPAI in wild birds. 

These virus strains can travel in wild birds without them appearing sick. People should avoid contact with sick/dead poultry or wildlife. If contact occurs, wash your hands with soap and water and change clothing before having any contact with healthy domestic poultry and birds.

All bird owners, whether commercial producers or backyard enthusiasts, should continue to practice good biosecurity, prevent contact between their birds and wild birds, and report sick birds or unusual bird deaths to State/Federal officials, either through their state veterinarian or through USDA’s toll-free number at 1-866-536-7593.  Additional information on biosecurity for backyard flocks can be found at http://healthybirds.aphis.usda.gov.

Additional background

Avian influenza (AI) is caused by an influenza type A virus which can infect poultry (such as chickens, turkeys, pheasants, quail, domestic ducks, geese and guinea fowl) and is carried by free flying waterfowl such as ducks, geese and shorebirds. AI viruses are classified by a combination of two groups of proteins: hemagglutinin or “H” proteins, of which there are 16 (H1–H16), and neuraminidase or “N” proteins, of which there are 9 (N1–N9). Many different combinations of “H” and “N” proteins are possible. Each combination is considered a different subtype, and can be further broken down into different strains. AI viruses are further classified by their pathogenicity (low or high)— the ability of a particular virus strain to produce disease in domestic chickens.

The current viruses are related to the HPAI H5N8 virus which originated in Asia and spread rapidly along wild bird migratory pathways during 2014, including the Pacific flyway. In the Pacific flyway, the HPAI H5N8 virus has mixed with North American avian influenza viruses, creating new mixed-origin viruses. These mixed-origin viruses contain the Asian-origin H5 part of the virus, which is highly pathogenic to poultry. The N parts of these viruses came from North American low pathogenic avian influenza viruses.

USDA has identified two mixed-origin viruses in the Pacific Flyway: the HPAI H5N2 virus and new HPAI H5N1 virus. The new HPAI H5N1 virus is not the same virus as the HPAI H5N1 virus found in Asia, Europe and Africa that has caused some human illness. The HPAI H5N2 virus has been detected in the Pacific, Central and Mississippi Flyways. 

Detailed analysis of the virus is underway in cooperation with the U.S. Centers for Disease Control and Prevention (CDC).  For more information about the ongoing avian influenza disease incident visit the APHIS website. More information about avian influenza can be found on the USDA avian influenza page. More information about avian influenza and public health is available on the CDC website.

 

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