Evaluation of strategies for control of sheep lice (Damalinia ovis) with an epidemiological model

A model was constructed to integrate the epidemiology and economics of control of sheep lice in Victoria and provide an objective basis for comparing lice control strategies. The strategies evaluated included different allocations of Department of Agriculture and Rural Affairs (DARA) resources for detection and supervision of infected flocks and for extension to enhance owner detection rates, change treatment practices or promote the adoption of disease prevention measures. Changes in prevalence and the net present cost of sheep lice to the industry were calculated over a 10-year period. The model predicted that the most profitable lice control strategy was to discourage routine annual treatment, promote treatment on detection, and encourage the adoption of lice prevention measures. The number of infested flocks undertaking eradication programs under DARA supervision had little effect on the prevalence or net cost of lice to Victoria.