Public Veterinary Medicine: Regulatory Medicine - Oval vesicular lesions in horses without evidence of vesicular stomatitis virus infection

Objective-To report clinical and serologic findings in horses with oral ves icular lesions that were consistent with vesicular stomatitis (VS) but appa rently were not associated with VS virus (VSV) infection. Design-Serial case study. Animals-8 horses. Procedure-Horses were quarantined after appearance of oral lesions typical of VS. Severity of clinical signs was scored every 2 to 5 days for 3 months . Serum samples were tested for antibodies by use of competitive ELISA (cEL ISA), capture ELISA for IgM, serum neutralization, and complement fixation (CF). Virus isolation was attempted from swab specimens of active lesions. Results-2 horses with oral vesicular lesions on day 1 had antibodies (cELIS A and CF) against VSV; however, results of CF were negative by day 19. Five of the 6 remaining horses were seronegative but developed oral lesions by day 23. Virus isolation was unsuccessful for all horses. Conclusions and Clinical Relevance-Horses were quarantined for 75 days in c ompliance with state and federal regulations. However, evidence suggests th at oral lesions were apparently not associated with VSV infection. The occu rrence in livestock of a vesicular disease that is not caused by VSV could confound efforts to improve control of VS in the United States and could im pact foreign trade. Vesicular stomatitis is of substantial economic and reg ulatory concern.