Modeling control methods to manage the sylvatic plague in black‐tailed prairie dog towns

Abstract

AbstractBlack‐tailed prairie dogs (Cynomys ludovicianus) are a keystone species of shortgrass and midgrass prairies, and they are essential for successful reintroduction efforts of endangered black‐footed ferrets (Mustela nigripes). Sylvatic plague extirpates black‐tailed prairie dog colonies. We present a model to determine optimal control methods to sustain a black‐tailed prairie dog colony against the plague, including a recently developed vaccine. Our host submodel is a susceptible, exposed, infectious, vaccinated model, and our vector submodel is a susceptible, exposed, early‐stage and late‐stage infectious model with questing and on‐host vectors. Both submodels are hybrid ordinary differential and difference equation models to reflect the phenology of black‐tailed prairie dogs. Our model suggests vaccination efforts can substantially outperform previous control methods (e.g. reactive insecticidal dusting). Our model suggests that a vaccine that provides 18 months of immunity, administered annually, starting one year before an outbreak, can efficiently sustain a black‐tailed prairie dog colony against the plague.Recommendations for resource managers The current sylvatic plague vaccine, administered annually, is insufficient to protect a black‐tailed prairie dog colony against the sylvatic plague. Developing a vaccine with an immunity period of 18 months is critical for the persistence of a colony against the plague. While insecticidal dusting appears unable to assist in helping a black‐tailed prairie dog colony recover from a plague outbreak, insecticidal dusting is still a critical prevention tool as plague transmission from the prairie dog flea is capable of causing a plague outbreak by itself. Black‐tailed prairie dog colony recovery efforts appear sensitive to regularly administered culling. We recommend that colonies that are designated as part of the black‐footed ferret recovery program be protected from population losses from recreational hunting and poisoning.