A randomized, placebo-controlled trial of the efficacy of
pyrantel (single dose 12.5 mg/kg bodyweight),
mebendazole (single 500 mg dose) and
albendazole (single 400 mg dose) in the treatment of
hookworm infections (Necator americanus) was carried out in January 1998 in the Southern Region of Mali, West Africa, during the period of Ramadan (Islamic fast). Statistical analysis of the pre-intervention faecal egg counts showed that there was a significant pre-treatment chance bias, despite randomization of subjects into treatment groups, arising from the main effect of sex (heavier
infections among males) and a sex x treatment interaction (the sex bias was not evident in the
pyrantel-treatment group). The participants were re-examined 10 days
after treatment, and after controlling for the drift in faecal egg counts in the placebo-treated subset, age, sex, fasting and intensity of
infection,
albendazole was clearly the most effective
drug showing consistently efficacies in the range 92.1 to 99.7%, depending on the method of evaluation and the particular subset of the treatment group. Neither
mebendazole nor
pyrantel was as effective, with efficacies ranging from 60.9 to 89.8% and 4.8 to 89.7%, respectively. Fasting made no difference to
drug efficacy. On the basis of our results the single 400 mg dose of
albendazole is the treatment of choice for
hookworm infections in this region of Mali. We emphasize the need for standardization of the methods used for trial designs, for calculation of summary data relating to
drug efficacies and the accompanying statistical tests.