The Texas Animal Health Commission (TAHC) is warning commercial poultry operators, farmers and rural residents who raise or maintain poultry on their premises to exercise caution after the United States Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed the presence of highly pathogenic (HPAI) H5 avian influenza in wild birds in Whatcom County, Washington, earlier this week.

Texas State Veterinarian, Dr. Dee Ellis, says he’s seen no reports of those influenza strains detected or suspected in commercial or private poultry operations in the state. But because of the nature and risks associated with these avian influenza strains, TAHC is advising poultry operators to maintain vigilance and to exercise caution in monitoring for and protecting against this biosecurity threat.

Two separate virus strains were identified and confirmed this week by USDA-APHIS: HPAI H5N2 in northern pintail ducks and HPAI H5N8 in captive Gyrfalcons that were fed hunter-killed wild birds. Officials emphasize neither virus has been found in commercial poultry anywhere in the United States and no human cases with these viruses have been detected in the United States, Canada or internationally. There is no immediate public health concern with either of these avian influenza viruses.

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Both H5N2 and H5N8 viruses have been found in other parts of the world but have not caused any human infection to date. While neither virus has been found in commercial poultry, federal authorities with the U.S. Department of Agriculture also emphasize that poultry, poultry products and wild birds are safe to eat even if they carry the disease if they are properly handled and cooked to a temperature of 165 degrees Fahrenheit.

Reported outbreaks

Outbreaks of avian influenza A occur among U.S. poultry flocks from time to time. Since early February 2004, avian influenza outbreaks have been reported in several locations in the United States, including Texas where an outbreak of the highly pathogenic avian influenza A (H5N2) among poultry occurred on a farm in Gonzales County in south-central Texas. This was the first outbreak of highly pathogenic avian influenza in the United States in 20 years and was detected by routine state monitoring for avian influenza.

Earlier this month (Dec. 4) Canadian health officials confirmed highly pathogenic H5N2 avian flu in two of the four H5-related poultry outbreaks in British Columbia's Fraser Valley near Vancouver, one of several evolving stories on avian flu outbreaks around the world.

Canada's chief veterinary officer said in a press briefing this week that test results on turkeys at a farm in Abbotsford and on chickens at a farm in Chilliwack confirmed highly pathogenic H5N2. Two other farms in Abbotsford and Chilliwack that received chickens from the first Chilliwack farm have birds that tested positive for the H5 strain.

The H5N8 influenza strain is a fast-spreading flu with potential risks of rapid movement among avian varieties. Germany, the Netherlands and the United Kingdom have recently identified outbreaks of H5N8 avian influenza. The first was reported on November 5 this year on a turkey farm in Mecklenburg-Vorpommern, Germany. The virus was identified as highly pathogenic avian influenza A (H5N8). This is the first detection of this strain of avian influenza, also called bird flu, in Europe, although outbreaks continue in wild birds and poultry in Asia

Following existing avian influenza response plans, USDA is working with the U.S. Department of the Interior and the U.S. Department of Health and Human Services, as well as State partners, on additional surveillance and testing of both commercial and wild birds in the nearby area.

Wild birds can be carriers of HPAI viruses without the birds 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.

Economic impact

HPAI would have significant economic impacts if detected in U.S. domestic poultry.  Commercial poultry producers follow strict biosecurity practices and raise their birds in very controlled environments. Federal officials emphasize that all bird owners, whether commercial producers or backyard enthusiasts, should continue practicing good biosecurity. This includes preventing contact between your birds and wild birds, and reporting sick birds or unusual bird deaths to State/Federal officials, either through your 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 healthybirds.aphis.usda.gov.

Avian influenza (AI) is caused by influenza type A viruses which are endemic in some wild birds (such as wild ducks and swans) that can infect poultry (such as chickens, turkeys, pheasants, quail, domestic ducks, geese and guinea fowl).

AI viruses are classified by a combination of two groups of proteins: hemagglutinin or “H” proteins, of which there are 17 (H1–H17), and neuraminidase or “N” proteins, of which there are 10 (N1–N10). 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 — the ability of a particular virus to produce disease in domestic chickens.

For more information visit the USDA avian influenza page and the USDA APHIS avian influenza page. For more information on avian influenza and wild birds, please visit the USGS National Wildlife Health Center.