The effect of farm management strategies on the incidence of sheep strike in Britain: a simulation analysis.

A deterministic model is used to simulate the seasonal incidence of sheep myiasis (strike) on farms in Britain and to explore the effects of different farm management strategies on strike incidence. The model is based on two sub-components: the seasonal pattern of abundance of the primary agent of sheep myiasis in northwest Europe, the blowfly Lucilia sericata and the range of factors known to influence ewe and lamb susceptibility to strike. The results of these simulations show that familiar farm management strategies, such as shearing, reduction in scouring caused by endoparasitic worms and insecticide use can have an important role in the reduction of strike incidence in ewes and lambs. However, the effectiveness of these techniques can be highly dependent of their timing in relation to seasonal changes in blowfly abundance and the effects of temperature and rainfall.