| Abstract: | I describe addition of a submodel representing dynamics of host resistance to the cattle fever tick (Boophilus microplus) to the simulation model of host-parasite-Iandscape interactions developed by Teel et al. (1996). The new submodel represents acquisition and loss of host resistance as a function of breed of cattle and history of exposure to ticks. The entire model is formulated as a deterministic compartment model based on difference equations and runs with a daily time-step. Model evaluation consisted of examining (1) ability of the new submodel to represent basic dynamics of host resistance in a manner consistent with available information and (2) sensitivity of model predictions of host resistance to changes in values of key model parameters. When host resistance rises above the naive level, the number of ticks sustained on the host are reduced and a constant, lower number of ticks are maintained on the animal. The maximum resistance capacity varies according to breed and IS the most sensitive component used in calculating the relative resistance mortality factor that increases larval mortality. Thus the new submodel appears to integrate available information on cow resistance to ticks in a manner capable of simulating the basic dynamics of resistance acquisition, maintenance, and loss. |
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