Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/30/2005
Publication Date: 11/5/2005
Citation: Koster, L., Landgraf, J., Swenson, S., Rodamaker, M., Emery, M., Smoliga, G.R., Rodriguez, L.L. 2005. Diagnostic evaluation of a reverse transcribed real time PCR assay for vesicular stomatitis in horses. American Association of Veterinary Laboratory Diagnosticians 48th Annual Conference. P. 92. Interpretive Summary:
Technical Abstract: Vesicular stomatitis (VS) is a viral infection that affects a variety of domesticated species including cattle, sheep, pigs, and horses. The symptoms vary among species, but VS usually manifests as vesicles on the epithelium of the nose, tongue, mouth, udder, and coronary bands. Vesicular stomatitis is an Office International des Epizooties (OIE) list disease that requires reporting of the disease to OIE. Vesicular stomatitis is found mainly in the southwestern parts of the United States into South America. While the disease is found sporadically in the southwestern United States, it is considered a foreign animal disease (FAD) and reportable to state and federal authorities. In pigs and ruminants the clinical signs are similar to foot-and-mouth disease (FMD) so rapid diagnosis of VS is extremely important to differentiate it from FMD. Horses are not susceptible to FMD, but VS is of considerable economic importance to owners as a result of quarantines, movement/trade restrictions, ill animals, and the cost of laboratory testing for movement purposes. In the most recent VS outbreaks, horses were the predominant species affected, so rapid diagnosis in horses allows animal health officials to monitor the spread of the disease. A single tube multiplex reverse transcribed real-time PCR (RRT-PCR) assay was developed by ARS to detect nucleic acid of vesicular stomatitis Indiana and New Jersey serogroup viruses in samples of vesicles. Validation of the test has focused primarily on ruminant samples due to the need to differentiate VS from FMD. We are seeking to extend its use to include horses and also to include swab samples as an additional sample type. For validation purposes, the RRT-PCR results are being compared to results for virus isolation with supplemental information as VS serologic results supporting a diagnosis. The Diagnostic Virology Laboratory at the National Veterinary Services Laboratory, in Ames, IA, receives FAD investigation samples for VS investigations in horses. The results from the testing at DVL will add to the validation process and provide data on the robustness of the protocol under field sampling and storage conditions that would not be reproduced during experimental infection studies. The RRT-PCR has the potential to be a rapid and inexpensive test that can be used to supplement and/or replace virus isolation for identification and typing of viruses that cause vesicular stomatitis in field submissions. This will allow for better monitoring and more rapid diagnosis of vesicular stomatitis infections. The data presented will include RRT-PCR and virus isolation results format the 2004 and 2005 outbreaks. Data analysis is currently in progress. To date, approximately 500 equine FAD samples and 100 negative controls have been tested.