Experiences with mass chemotherapy in the control of schistosomiasis in Mali

Mass chemotherapy using praziquantel in a single dose of 40 mg/kg was the main strategy of schistosomiasis control in Mali during the intervention phase. Treatment was applied either indiscriminately to all inhabitants over the age of two years of a given village or as a case treatment to those found infected during a previous parasitological examination. In one study area, only children aged 5 to 15 were treated if they had been found infected. According to the variables: type of treatment, parasite species, interval between intervention and follow-up survey, baseline prevalence, and ecological environment, 13 groups of villages were formed, comprising a minimum of five settlements and/or 600 inhabitants. The highest reductions of general or intensive infections were found when blanket mass treatment had been used in Schistosoma haematobium and if the follow-up was after one year. A significant reduction of S. haematobium prevalence was seen even three years after age specific case- or blanket treatment in non-specific savanna villages. Control was least successful with S. mansoni infections in irrigated areas.