Modelling the potential benefits of different strategies to control infection with Trypanosoma evansi in camels in Somaliland.

Trypanosoma evansi (T. evansi), the protozoan parasitic cause of camel trypanosomosis (Surra), constitutes one of the major veterinary problems worldwide. An infectious disease model of camel trypanosomosis (Surra) was adopted from one developed for buffalo and applied to study the impact of T. evansi infection on camel production. The model contained deterministic and stochastic components and the seroprevalence based on a survey conducted in Somaliland in 2011 and 2012 to simulate and estimate the economic benefits of four different control options against T. evansi infection in camels (1, 2, 3 and 4 regimens). The mean benefit per animal of controlling surra was calculated at US$354 (the treatment of all camels biannually), US$426 (the monthly targeted treatment of clinically sick camels) and US$287 (biannual targeted treatment of seropositive camels), respectively, compared with US$137 for untreated camels. Consequently, the model predicted that the total net benefit loss to a camel herd or village that was not applying the recommended effective surra control strategy was US$115,605 (69.4 billion shilling per annum).