Effects of the canine rattlesnake vaccine in moderate to severe cases of canine crotalid envenomation

This is a retrospective multicenter study (2006–2012) examining a population of dogs with moderate to severe crotalid envenomation for protective effects of the canine rattlesnake vaccine. Five nonacademic emergency and referral veterinary hospitals in Southern California were involved in the study and contributed records regarding a total of 82 client-owned dogs that were treated for naturally occurring rattlesnake envenomation. All dogs received antivenin (Crotalidae) polyvalent, with dosages ranging from one to three vials (mean: 1.3±0.6). Fourteen dogs (17%) had a history of prior vaccination against crotalid venom. In univariate logistic regression modeling, cases with lower body weight (P=0.0001) or higher snakebite severity scores (P<0.0001) were associated with greater morbidity. No statistically significant difference in morbidity or mortality between vaccinated and unvaccinated dogs was found. The findings of this study did not identify a significantly protective effect of previous vaccination in the cases of moderate to severe rattlesnake envenomation that require treatment with antivenin.