Highly pathogenic avian influenza confirmed in wild bird in South Carolina

WASHINGTON — The United States Department of Agriculture’s Animal and Plant Health Inspection Service has confirmed highly pathogenic Eurasian H5 avian influenza in a wild American wigeon in Colleton County, South Carolina.

Eurasian H5 HPAI has not been detected in a wild bird in the United States since 2016. There was a case of HPAI (H7N3) in one commercial meat turkey flock in South Carolina in 2020 due to a North American lineage virus.

Low risk

The Centers for Disease Control and Prevention considers the risk to the general public from HPAI H5 infections to be low. No human infections with Eurasian H5 viruses have occurred in the United States.

As a reminder, the proper handling and cooking of poultry and eggs to an internal temperature of 165 degrees kills bacteria and viruses, including HPAI.

Anyone involved with poultry production from the small backyard to the large commercial producer should review their biosecurity activities to assure the health of their birds.

APHIS has materials about biosecurity, including videos, checklists, and a toolkit available at aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/defend-the-flock-program/dtf-resources/dtf-resources.

APHIS Wildlife Services collected the sample from the hunter-harvested American wigeon, and it was initially tested at the Clemson Veterinary Diagnostic Center (a member of the National Animal Health Laboratory Network). The presumptive positive samples were then sent to APHIS’ National Veterinary Services Laboratories for confirmatory testing.

Since wild birds can be infected with these viruses without appearing sick, people should minimize direct contact with wild birds by using gloves. If contact occurs, wash your hands with soap and water, and change clothing before having any contact with healthy domestic poultry and birds.

Hunters should dress game birds in the field whenever possible and practice good biosecurity to prevent any potential disease spread.

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 USDA’s toll-free number at 866-536-7593.

Additional background

Avian influenza 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 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 chickens.