The costs and a cost-benefit analysis of an S. mansoni control programme on an irrigated sugar estate in northern Tanzania.

On a sugar estate in northern Tanzania, an integrated control programme against Schistosoma mansoni was carried out during the three years 1968-70 inclusive. The costs of that programme are defined, the costs of future snail control in the same area are estimated, and an attempt is made to evaluate the cost-benefit ratio of schistosomiasis control in the estate. The total expenditure on snail control was US $23 538, of which US $17 371 was spent on molluscicides and US $5 135 on labour. This represents an annual expenditure of approximately US $1.31 per estate resident. In the mass diagnosis and treatment campaign the main items in the total expenditure of US $37 043 were labour (US $13 724), drugs (US $4 218), hospital charges (US $8 262), and lost working days (US $8 760). It is estimated that the recurrent annual expenditure necessary to keep S. mansoni at a low level in the future would be US $7 714 on snail control and US $1 832 on detecting and treating new cases; however, the institution of a snail control programme would reduce the need for chemotherapy and would result in recurrent annual savings of US $7 448. In addition, it was estimated from a productivity study that savings of about US $14 000 per year could result if treatment of infected workers raised productivity by 5%. The goodwill that resulted from the protection of wives and children against schistosomiasis would be a further benefit. When all factors are taken into account, snail control appears to be a feasible economic proposition.