Long-term efficacy of single-dose oral treatment in schistosomiasis haematobium

Abstract

A two-year follow-up was conducted in children who had been the subjects of a six-month double-blind trial in the single-dose treatment of Schistosoma haematobium infection. The trial had assessed therapeutic efficacy of three oral preparations—praziquantel 40 mg/kg, metrifonate 10 mg/kg, and the “combination” (concurrent niridazole 25 mg/kg and metrifonate 10 mg/kg administration). Reduction in urinary egg excretion remained high up to follow-up at two years, based on a comparison of pre- and post-treatment geometric mean counts—praziquantel 96·9% (n = 96 at six months, 51 at two years); the ‘combination’ 93·9% (n = 97 at six months, 48 at two years); and metrifonate 90·3% (n = 92 at six months, 49 at two years). The differences in percentage reduction were not significant (p>0·1). However, a significantly greater reduction in egg ouput was produced by praziquantel (81·7%) and the ‘combination’ (82·5%) than by metrifonate (54·2%), on comparing pre- and post-treatment arithmetic mean counts (p<0·01). A significantly smaller percentage of subjects were excreting ≥125 ova/10 ml urine two years after treatment with praziquantel (10·3%), compared to treatment with the ‘combination’ (25·7%) and metrifonate (35·8%) (p<0·01). The cure rate was significantly higher in the praziquantel group (47·4%) compared to the ‘combination’ (24·7%) and metrifonate (17·4%) groups, for the six to 24-month follow-up period (p<0·001). The pattern and level of transmission had contributed to the long-term efficacy recorded in this study.