Multiyear surveillance for avian influenza virus in waterfowl from wintering grounds, Texas coast, USA

Abstract

We studied the prevalence of influenza A virus in wintering waterfowl from the Central Flyway on the Gulf Coast of Texas. Of 5,363 hunter-harvested migratory and resident waterfowl and wetland-associated game birds sampled during 3 consecutive hunting seasons (September-January 2006-07, 2007-08, and 2008-09), real-time reverse transcription-PCR detected influenza A matrix sequences in 8.5% of samples, H5 in 0.7%, and H7 in 0.6%. Virus isolation yielded 134 influenza A viruses, including N1-N9, H1-H7, H10, and H11 subtypes. Low-pathogenicity H7 subtype was isolated during January, September, and November 2007 and January 2008; low-pathogenicity H5 subtype was isolated during November and December 2007.

Figure

Locations of state wildlife management areas where samples were collected from waterfowl for avian influenza virus surveillance, Texas mid–Gulf Coast, USA, September–January 2006–07, 2007–08, and 2008–09. Inset shows location of Texas (shaded).