Comparative sensitivity of the VecTest antigen-capture assay, reverse transcriptase-PCR, and cell culture for detection of West Nile virus in dead birds

The sensitivity of the VecTest antigen-capture and RT-PCR assays were compared to brain tissue culture in Vero cells for the detection of WNV in a sample of dead birds collected in East Texas and southern Louisiana during the summer of 2003. Cell culture was used as the gold standard, because it yielded the most positives. Direct culture of brain tissue and the WNV antigen-capture assay, done on oropharyngeal swabs, gave statistically comparable results (46% and 40% positive, respectively). In contrast, RT-PCR done on brain homogenates was significantly less sensitive than direct tissue culture (33% compared to 46%, respectively). Results indicated that RT-PCR may not be consistently the most sensitive assay for detection of WNV in dead bird brain tissue and that the VecTest antigen-capture assay has a number of advantages over the other two detection techniques for routine surveillance activities.