Management factors affecting the risk for vesicular stomatitis in livestock operations in the western United States

Objective-To identify management factors affecting the risk of animals deve loping vesicular stomatitis (VS). Design-Case-control study. Animals-Horses, cattle, and sheep with suspected vesicular stomatitis on 39 5 premises in Colorado, New Mexico, Utah, and Arizona. Procedure-Data were collected during the VS outbreak of 1997. Diagnostician s interviewed livestock owners and completed a supplemental questionnaire. Cases were defined as those premises that had a completed questionnaire and had greater than or equal to 1 animal positive for VS. Control premises we re all premises investigated that had a completed questionnaire and on whic h the animals had been tested but VS was not detected. Results-Animals that had access to a shelter or barn had a reduced risk of developing VS (OR, 0.6; 95% confidence interval [CI], 0.35 to 0.99). This e ffect was more pronounced for equine premises (OR, 0.5; 95% CI, 0.3 to 0.9) . Conversely, during an adjusted analysis on equine premises, risk of devel oping disease was increased slightly where animals had access to pasture (O R, 2.01; 95% CI, 1.1 to 3.7). On all premises where owners reported insect populations were greater than normal, odds of developing disease were signi ficantly increased (OR, 2.5; 95% CI, 1.47 to 4.47). Premises with animals h oused < 0.25 miles from running water were more than twice as likely to hav e clinical signs of VS (OR, 2.6; 95% CI, 1.32 to 5.0). Conclusions and Clinical Relevance-These results support reports of others that suggest biting insects are a vector in VS virus transmission. Manageme nt practices to reduce exposure to biting insects might reduce the risk of VS.