USDA’s Animal and Plant Health Inspection Service (APHIS) on Sunday confirmed the presence of highly pathogenic H7 avian influenza (HPAI) of the North American wild bird lineage in a commercial chicken breeder flock in Lincoln County, Tennesse, along the Mississippi flyway. This is the first confirmed case of HPAI in commercial poultry in the United States this year.
A broiler breeder farm contains roosters and hens known as “parent stock” that produce fertilized eggs, which hatch into the broiler chickens that become meat.
“All U.S. flocks are tested year-round for avian influenza, and if a single bird in a flock were to test positive for avian flu, then none of those birds would be allowed to enter the food supply,” said Dr. Ashley Peterson, NCC’s senior vice president of scientific and regulatory affairs, in a statement on Sunday. “NCC is encouraging its members to maintain heightened biosecurity protocols,” Peterson added. “We will also be working with our government and trading partners to minimize any potential disruptions to our export markets.”
USDA’s National Veterinary Services Laboratories has confirmed the full subtype for the highly pathogenic H7 avian influenza. The virus has been identified as North American wild bird lineage H7N9 HPAI based upon full genome sequence analysis of the samples.
The laboratory found that all eight gene segments of the virus are North American wild bird lineage. This is not the same as the China H7N9 virus that has impacted poultry and infected humans in Asia, APHIS said in a news release. While the subtype is the same as the China H7N9 lineage that emerged in 2013, this is a different virus and is genetically distinct from the China H7N9 lineage, APHIS said.
USDA continues to work with the Tennessee Department of Agriculture on the joint incident response. State officials quarantined the affected premises and birds on the affected premises have been depopulated. An epidemiological investigation is underway to determine the source of the infection.
Federal and state partners continue to conduct surveillance and testing of poultry within a expanded 10-mile radius around the affected premises to ensure all commercial operations in the area are disease-free. In addition, strict movement controls are in place within an established control zone to prevent the disease from spreading. As of Wednesday, all commercial premises within the surveillance area had been tested, and all of the tests from the surrounding facilities were negative for disease. Officials will continue to observe commercial and backyard poultry for signs of influenza, and all flocks in the surveillance zone will be tested again.
State agriculture officials said yesterday that no additional cases of avian influenza have been found within a 10-mile radius of the broiler breeder farm. No additional poultry within the surveillance area have shown signs of illness. And, all samples from poultry within the area have tested negative for HPAI.
However, yesterday, Tennessee’s state veterinarian confirmed that a flock of chickens at a commercial breeding operation in Giles County has tested positive for low pathogenic avian influenza. Routine screening of the premises in Giles County indicated the presence of avian influenza in the flock. State and federal laboratories confirmed the existence of H7N9 low pathogenic avian influenza in tested samples. The company that operates this facility is a different company from the one associated with the outbreak of HPAI in Lincoln County.
As a result, and as a precaution, the affected flock was depopulated. The premise is under quarantine. Domesticated poultry within a 6.3 miles radius of the site are also under quarantine and are being tested and monitored for illness. Thus far, all additional samples have tested negative for avian influenza and no other flocks within the area have shown signs of illness.
Meanwhile, a strain of low pathogenic H5N2 avian flu was discovered in a flock of 84,000 turkeys in Barron County, Wisconsin, USDA said. The infected premises were quarantined. Low pathogenic avian influenza typically causes few or no clinical signs in birds. USDA said tests have shown that the H5N2 virus detected in Wisconsin was of North American wild bird origin and distinct from the H5N2 virus found in 2014 and 2015 during a widespread outbreak of HPAI.
Avian flu is not a foodborne illness, which means it cannot be contracted from eating poultry that has been cooked properly. And in the event a flock does test positive, as in this case in Tennessee, it will not enter the food chain. Additionally, the risk of humans contracting avian flu is very low, according to the Centers for Disease Control and Prevention.
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, APHIS said.
Additional information is available from the USDA’s Animal and Plant Health Inspection Services and from the Tennessee Department of Agriculture.
