A spatially aggregated disease/host model for bovine Tb in New Zealand possum populations.
Deterministic disease/host models based on differential equations, with and without age-structure, are used to aid understanding of the epidemiology of bovine tuberculosis (Tb) in New Zealand possum (Trichosurus vulpecula) populations. Because of the patchiness of bovine Tb in possum populations the classic models are modified to include spatial aggregation of the disease, which is quantified using field data. Three scenarios for the disease are considered: chronic with short latent period, acute with long latent period and acute with short latent period, of which the latter is considered the most likely. The basic reproductive rate for the disease, Ro, is approximately 1.8-2.00 for all of the scenarios. It is suggested that the transmission coefficient for the disease (β) varies inversely with the possum carrying capacity (K) explaining why prevalence and disease dynamics vary little with K or the habitat.