Vaccination strategies to conserve the endangered African wild dog (Lycaon pictus)

Pathogens such as rabies virus and canine distemper virus present a significant risk to the long-term survival of some endangered African wild dog (Lycaon pictus) populations. Vaccination of wild dogs is one approach that might reduce population extinction risks; however clear guidelines for how best to do this are lacking. Hence, we developed a mathematical model of wild dog population dynamics that integrates a pathogen transmission model and a vaccination process. Simulations indicated that the most effective vaccination strategy includes all age classes (when pups are 2-months old), prioritizes the breeding pair, and vaccinates at least 4 animals per pack included in the vaccination effort. In addition, populations for which an Allee effect, high rates of pathogen introduction, or low rates of recovery and immunity were simulated, required greater vaccination coverage (dogs/pack), to protect an equivalent number of packs compared to populations for which no Allee effect, low rates of pathogen introduction, or high rates of recovery and immunity were simulated. For populations in which some packs (high-risk) have a greater risk of pathogen exposure than others (low-risk), vaccinating both high- and low-risk packs, or only low-risk packs, is more effective than vaccinating only high-risk packs when pathogen introduction rates are high. Finally, model results suggest that vaccination of wild dog populations against pathogens, such as canine distemper virus, that do not cause 100% mortality and against which some wild dogs develop acquired immunity, may be unnecessary.