Ranking control options for tropical theileriosis in at-risk dairy cattle in Tunisia, using benefit-cost analysis.

An economic evaluation of various control programmes against Theileria annulata infection was conducted on a sample of 49 Tunisian dairy farms where clinical cases of tropical theileriosis had been recorded during the summer. Indicators of morbidity and the prevalence of infection, as well as production and demographic indicators (recorded in the present survey ortaken from secondary sources), were used to rank the potential costs and benefits of various control programmes for tropical theileriosis over a time horizon of 15 years. Three options were considered, i.e. vaccination with a local attenuated cell-line vaccine; partial barn upgrading, based on first roughcasting then smoothing all the walls of the animal premises (inner and outer surfaces); and applying acaricides to control the vector tick population on the cattle. The most important loss from this disease, representing between 22% and 38% of the overall losses, is the loss in milk yield from carriers of T. annulata. Upgrading barns produced the highest mean benefit-cost ratio (1.62 to 3.71), while the ratios for vaccination and acaricides ranged from 0.20 to 1.19 and 0.32 to 0.88, respectively. However, the benefit-cost ratio of vaccination increased (from 1.65 to 5.41), when the costs due to carrier state infection, which vaccination does not prevent, were ignored. Upgrading barns is a sustainable eradication policy against tropical theileriosis, based on a single investment, and is environmentally friendly. This control option should be encouraged by national Veterinary Authorities in regions where tropical theileriosis is transmitted by a domestic endophilic tick.