Schistosomiais control based on repeated chemotherapy in rural village of sugar-cane zone in northeast Brazil

RESUMO

A schedule of repeated chemotherapy with oxamniquine, consisting of biannual treatment of school-aged (7-13 years) children and annual treatment of all other age groups, was used in a representative rural village from a highly endemic area of schistosomiasis in Pernambuco. Significant reductions in infection were obtained only after two cycles of treatment, as the overall prevalence decreased from 72.6 per cent to 41.7 per cent and the geometric mean egg counts per gram of faeces among positives fell from 188.4 to 76. In a school-aged cohort (n=29) three treatment at six-month intervals were necessary to significantly reduce the proportion of positive (from 75.9 per cent to 51.7 per cent). In a cohort of children under 7 years of age (n=20) the proportion of positives actually increased (from 30 per cent to 45 per cent) despite two annual treatments. Water contact was intense and host snails density was relatively high. As there is no short-term perspective of improved sanitation, auxiliary measures such as focal mollusciciding are needed for an adequate control of schistosomiasis in this and alike areas.