The United States Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed a second case of highly pathogenic H7N9 avian influenza in a commercial breeder flock in Lincoln County, Tennessee. This H7N9 strain is of North American wild bird lineage and is the same strain of avian influenza that was previously confirmed in Tennessee. It is NOT the same as the China H7N9 virus that has impacted poultry and infected humans in Asia. The flock of 55,000 chickens is located in the Mississippi flyway, within three kilometers of the first Tennessee case.
Samples from the affected flock, which displayed signs of illness and experienced increased mortality, were tested at Tennessee’s Kord Animal Health Diagnostic Laboratory and confirmed at the APHIS National Veterinary Services Laboratories (NVSL) in Ames, Iowa.
USDA is working with the Tennessee Department of Agriculture on the joint incident response. State officials quarantined the affected premises, and depopulation has begun. Federal and State partners will conduct surveillance and testing of commercial and backyard poultry within a 10 kilometer (6.2 mile) radius of the site.
The United States has the strongest AI surveillance program in the world, and USDA works with its partners to actively look for the disease in commercial poultry operations, live bird markets and in migratory wild bird populations.
USDA will be informing the World Organization for Animal Health (OIE) as well as international trading partners of this finding. USDA also continues to communicate with trading partners to encourage adherence to OIE standards and minimize trade impacts.
The Tennessee Department of Agriculture is working directly with poultry workers at the affected facilities to ensure that they are taking the proper precautions to prevent illness and contain disease spread. As a reminder, the proper handling and cooking of poultry and eggs to an internal temperature of 165 ?F kills bacteria and viruses.
Wild waterfowl are natural hosts for avian influenza, including H5 and H7, and can shed the virus without appearing sick. These low pathogenic viruses can mutate to highly pathogenic forms after introduction to poultry. 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 commercial producers can be found at www.aphis.usda.gov/animalhealth/defendtheflock Information for backyard producers can be found at https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian-influenza-disease/birdbiosecurity
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.