Bird flu can strike twice. A commercial turkey flock in Dubois County, Indiana, last struck by highly pathogenic avian influenza (HPAI) in 2016,  is again infected as the disease returns to America..

The USDA’s Animal and Plant Health Inspection Service (APHIS) confirms the presence of highly pathogenic avian influenza (HPAI) in a commercial turkey flock in Dubois County, IN. This one is the first confirmed case of HPAI in commercial poultry in the United States since 2020.

The report that the latest avian flu strain has infected a commercial flock of turkeys comes after wild birds in several southern states were found with the disease.

Avian influenza rarely results in human illnesses  No human cases of these first avian influenza viruses since 2020 have been detected in the United States. The USDA reminds the public that proper handling and cooking of poultry and eggs to an internal temperature of 165 ˚ F kill bacteria and viruses.

Samples from the affected flock, which experienced increased mortality, were tested at the Indiana Animal Disease Diagnostic Laboratory at Purdue University, part of the National Animal Health Laboratory Network, and confirmed at the APHIS National Veterinary Services Laboratories (NVSL) in Ames, IA. Virus isolation is ongoing.

APHIS is working closely with the Indiana Board of Animal Health on joint incident response. State officials quarantined the affected premises, and birds on the property were depopulated to prevent the spread of the disease. Birds from the flock will not enter the food system.

As part of existing avian influenza response plans, federal and state partners are working jointly on additional surveillance and testing in the nearby area. The United States has the strongest AI surveillance program in the world, and the 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.

Anyone involved with poultry production from small backyard flocks to the large commercial producers should review their biosecurity activities to assure the health of their birds. APHIS has materials about biosecurity, including videos, checklists, and a toolkit available on its website.

The USDA will report this finding to the World Organization for Animal Health (OIE) as well as international trading partners. The USDA also continues to communicate with trading partners to encourage adherence to OIE standards and minimize trade impacts.

OIE trade guidelines call on countries to base trade restrictions on sound science and, whenever possible, limit restrictions to those animals and animal products within a defined region that pose a risk of spreading the disease of concern.

In addition to practicing good biosecurity, all bird owners should 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 the USDA’s toll-free number at 866-536-7593. Additional information on biosecurity for backyard flocks can be found at

Avian influenza (AI) is caused by 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 which circulate within flyways/geographic regions. AI viruses are further classified by their pathogenicity (low or high) — the ability of a particular virus strain to produce disease in domestic poultry.

The United States experienced its largest outbreak of bird flu in 2014 and 2015 when 51 million birds were lost to the H5N2 disease.

In May and June 2015, 25 million birds were culled, equating to 409,836 birds per day, or 284 birds per minute. In total, the 2014-2015 H5N2/H5N8 outbreak cost U.S. poultry and egg producers $879 million with public expenditures going to eradicate the disease. 

In January 2016, the highly pathogenic avian influenza (HPAI) H7N8 virus was first reported at a commercial turkey flock in Dubois County, IN. Subsequently, APHIS reported the 2016 detection of low pathogenic avian influenza (LPAI) H7N8 among eight nearby turkey flocks. 

Avian influenza viruses are classified as either low pathogenic or highly pathogenic depending upon molecular characteristics of the virus and the virus’ ability to cause disease and mortality in chickens in a laboratory setting. Influenza viruses are constantly changing, and LPAI H7 viruses are known to rapidly evolve into HPAI viruses. Infection of poultry with LPAI viruses may cause no disease or mild illness, such as ruffled feathers and a drop in egg production, and may not be detected. Infection of poultry with HPAI viruses can cause severe disease with high mortality in birds. Both HPAI and LPAI viruses can spread rapidly through poultry flocks.

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