Published since 1946
Fall 2023 Surveillance for Highly Pathogenic Avian Flu in Wild Birds Underway, Positive Findings are Widely Distributed
Following the Implementation Plan for Avian Influenza Surveillance in Waterfowl in the United States: Summer 2023 – Spring 2024, fall activities began in September. Between 9/1/23 and 11/3/23, approximately 286 positive cases in wild birds have been identified. Surveillance includes both hunter-harvested birds and recovered mortality/morbidity birds.
Collaborating entities include the U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) Wildlife Services (WS) National Wildlife Disease Program (NWDP) and Veterinary Services (VS); the U.S. Department of the Interior (DOI) U.S. Geological Survey (USGS) and U.S. Fish and Wildlife Service (USFWS); and the National Flyway Council. The Implementation Plan supports the collection of biological samples, diagnostic testing, data management, and analysis of data obtained by USDA-APHIS-Wildlife Services (WS), other Federal agencies, State wildlife agencies, Universities, and Tribal cooperators.
Outbreaks of HPAI in commercial and backyard flocks have also been detected. Between 9/1/23 and 11/6/23, thirty-one commercial flocks and 24 backyard flocks have been identified as infected with HPAI in at least 16 states.
Avian influenza is caused by influenza Type A virus (influenza A). Avian-origin influenza viruses are broadly categorized based on a combination of two groups of proteins on the surface of the influenza A virus: 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 related viruses within a subtype may be referred to as a lineage. Avian influenza viruses are classified as either “low pathogenic” or “highly pathogenic” based on their genetic features and the severity of the disease they cause in poultry. Most viruses are of low pathogenicity, meaning that they causes no signs or only minor clinical signs of infection in poultry.
The current Highly Pathogenic Avian Flu outbreak began in March 2022. More than 16 million chickens, turkeys, ducks and other birds in Iowa — and 63 million birds nationally — in affected flocks have been destroyed in an attempt to contain the disease, according to the U.S. Department of Agriculture data.