Avian influenza virus investigation in wild bobwhite quail from Texas

The objective of this study was to determine the prevalence of avian influenza viruses (AIV) in bobwhite quail (Colinus virginianus) populations from the rolling plains of Texas, U. S. A. A total of 1320 swab samples (652 tracheal swabs and 668 cloacal swabs) and 44 serum samples were collected from wild-captured or hunter-harvested bobwhite quail from November 2009 to April 2011 at the Rolling Planes Quail Research Ranch, Fisher County, Texas, U. S. A. The presence of AIV in the swabs was determined by real-time reverse-transcription-PCR (rRT-PCR) and all samples positive or suspicious by rRT-PCR were further processed for virus isolation in embryonated chicken eggs. A total of 18 (1.4%) swab samples tested positive for AIV by rRT-PCR (cycle threshold [Ct] values < 35): 13 cloacal swabs (1.9%) and 5 tracheal swabs (0.8%). In addition, 100 (7.6%) swab samples were considered suspicious (Ct values 35.1-40): 69 cloacal swabs (10.3%) and 31 tracheal swabs (4.7%). No virus was isolated from any of the rRT-PCR-positive or suspicious samples tested. Additionally, 44 serum samples were screened for AIV antibodies and were negative. The results presented here indicate low prevalence of AIV in wild populations of bobwhite quail.