Identification of Type A Influenza Viruses from Wild Birds on the Delmarva Peninsula, 2007–10

SUMMARY Wild waterfowl and shorebirds in the Delaware-Maryland-Virginia (Delmarva) Peninsula region within the Atlantic Flyway were sampled as part of the Early Detection of Highly Pathogenic H5N1 Avian Influenza (AI) in Wild Migratory Birds program. The U.S. Department of Agriculture (USDA) and state wildlife agencies submitted 7858 samples for AI virus (AIV) testing by real-time reverse transcription PCR (rRT-PCR) to the University of Delaware Poultry Health System from April 2007 to March 2011. Virus isolation attempts were performed on samples with matrix gene cycle threshold (Ct) values ≤33.9. Using rRT-PCR, AIV was detected in 14% (1091/7857) of the samples. In species with sample sizes >100, American black duck (Anas rubripes; 28%), ruddy turnstone (Arenaria interpres; 27%), American green-winged teal (Anas crecca; 21%), semipalmated sandpiper (Calidris pusilla; 27%), greater snow goose (Chen caerulescens atlanticus; 12%), mallard (Anas platyrhynchos; 10%), and northern pintail (Anas acuta; 14%) sh...