THE IMPACT OF ZINC SUPPLEMENTATION ON SCHISTOSOMA-MANSONI REINFECTIONRATE AND INTENSITIES - A RANDOMIZED, CONTROLLED TRIAL AMONG RURAL ZIMBABWEAN SCHOOLCHILDREN

Objectives: To assess the effect of zinc supplementation on susceptibi lity to S. mansoni reinfections among schoolchildren. Design: Randomiz ed, double-blind, placebo-controlled trial. Setting and Subjects: 313 rural Zimbabwean schoolchildren (144 boys and 169 girls), 11-17 y). In terventions: Supplementation with zinc (30 or 50 mg) or placebo on sch ooldays for 12 months. Due to drought, a food programme was in operati on during the last eight months of the study. Outcome measures: S. man soni and S. haematobium reinfection rates and intensities. Results: Th ere was no difference in reinfection rates between the zinc and placeb o groups (25 vs 29%, P = 0.46). However, the median intensity of S. ma nsoni reinfection, although low in both groups, was significantly lowe r in the zinc than in the placebo group (7 vs 13 eggs per gram of faec es, P = 0.048). No difference in either S. haematobium reinfection rat es or intensities were seen. Conclusions: Zinc supplementation reduced the intensity of S. mansoni reinfections. Although the intensities of reinfection were very low, the finding probably reflects a biological effect of zinc that could be of public health importance in settings with higher transmission.