Chewable pyrantel pamoate tablets were administered to children randomly assigned to three treatment groups. Individuals in each group were instructed either to swallow whole, to chew and swallow, or to swallow previously pulverized tablets. With respect to Ascaris, results of posttreatment stool examinations indicated no differences in cure rates and egg reduction rates between the different modes of treatment. However, for both hookworm and Trichuris, mean egg counts increased for both swallow and chew groups, but decreased in the pulverized group. In addition to the highest egg reduction rates, the most parasitological cures were also seen in the pulverized group for these two worms. The status of standards for chewable tablets is discussed. Until the standards are changed it is recommended that all chewable tablets be crushed before swallowing.
Adolescent, Ascariasis - drug therapy, Hookworm Infections - drug therapy

Papua New Guinean schoolchildren in the highlands were randomly assigned to treatment groups in order to verify the effectiveness of mebendazole (Nordia) and compare it with mebendazole (Janssen) in both extended and single-dose therapy in a double-blind controlled study. Only the Janssen product given twice daily for three days was of value in 'curing' hookworm. Single-dose treatment with the same product was highly effective in treating roundworm but not hookworm or whipworm. Observations suggest that drug particle size may be an important determinant of efficacy against hookworm. Based on this study, the use of the Janssen formulation of mebendazole would be preferable.
Adolescent ; Child ; Double-Blind Method ; Helminthiasis - drug therapy ; Hookworm Infections - drug therapy ; Humans ; Mebendazole - pharmacology ; Papua New Guinea

OBJECTIVEOur objective was to systematically evaluate chemotherapy-based control of ascariasis and hookworm infection and make predictions of the effectiveness of repeated mass treatment at different levels of coverage in highly endemic areas of China.

METHODSField surveys were carried out to acquire the ascariasis and hookworm prevalence and intensity (mean worm burden) at baseline, one month and one year later. We calculated model parameters based on the survey data, then incorporated them into a quantitative framework to predict the prevalence and intensity one year later. Sensitivity analyses were performed to assess the influence of the chemotherapy measures on prevalence and intensity, and model simulations were performed to evaluate the feasibility of achieving the proposed transmission control criteria under different chemotherapy measures.

RESULTSThe predicted prevalence and intensity one year from baseline were within the 95% confidence interval of actual values. As treatment frequency or coverage increased, the prevalence and intensity decreased. Model simulations show that many rounds of treatment are needed to maintain the prevalence at a low level in highly endemic areas of China.

CONCLUSIONWe should select different combinations of treatment frequency, coverage and drug efficacy according to available resources and practical attainable conditions. Mathematical modeling could be used to help optimize the chemotherapeutic scheme aiming at specific parasitic species and areas, and to direct the establishment of soil-transmitted helminthiasis control criteria in China.

Anthelmintics ; therapeutic use ; Ascariasis ; drug therapy ; epidemiology ; prevention & control ; China ; epidemiology ; Computer Simulation ; Endemic Diseases ; prevention & control ; Hookworm Infections ; drug therapy ; epidemiology ; prevention & control ; Humans ; Models, Biological ; Prevalence ; Reproducibility of Results ; Time Factors

Animals ; Antinematodal Agents ; chemical synthesis ; therapeutic use ; toxicity ; Dogs ; Drug Resistance ; Female ; Haplorhini ; Hookworm Infections ; drug therapy ; microbiology ; Humans ; Male ; Mice ; Parasite Egg Count ; Pyridinium Compounds ; therapeutic use ; Rabbits ; Thiophenes ; therapeutic use