Emerg Infect DiseidEmerging Infectious Diseases1080-60401080-6059Centers for Disease Control115855412631755Research ArticleDetection of North American West Nile virus in animal tissue by a reverse transcription-nested polymerase chain reaction assay.JohnsonD. J.donna.j.johnson@aphis.usda.govOstlundE. N.PedersenD. D.SchmittB. J.Animal and Plant Health Inspection Service, U.S. Department of Agriculture, 1800 Dayton Ave., Ames, IA 50010-0844, USA.Jul-Aug200174739741

A traditional single-stage reverse transcription-polymerase chain reaction (RT-PCR) procedure is effective in determining West Nile (WN) virus in avian tissue and infected cell cultures. However, the procedure lacks the sensitivity to detect WN virus in equine tissue. We describe an RT-nested PCR (RT-nPCR) procedure that identifies the North American strain of WN virus directly in equine and avian tissues.