Trials using albendazole and mebendazole, as single 400 mg dose treatments, against soil-transmitted helminths, were carried out in 7-9 and 10-12 years-old schoolchildren living in urban and rural environments in Penang, Malaysia. Both drugs were equally effective in treating trichuriasis and ascariasis in both age groups and environments. However, mebendazole is not so effective in the treatment for hookworms when compared to albendazole. It is suggested that albendazole should be considered the drug of choice for mass chemotherapy for Penang.
Children with severe Trichuris trichiura infection pose significant social, clinical, and therapeutic problems in Malaysia. Thirty such children were investigated, and mebendazole was found to be safe and effective in the treatment of severe trichuriasis but it had to be given for a longer period than currently recommended. A poor correlation was found between egg load and worm burden in these children. Direct visualization of the rectal and colonic mucosa was the most reliable method of assessing severity in untreated cases, and response to treatment. The eggs of Trichuris that had been exposed to mebendazole were morphologically altered and not viable when incubated. This may be of considerable epidemiological importance.
A previous study had suggested that local strains of goat trichostrongyles, comprising largely Haemonchus contortus, might have developed resistance to benzimidazole anthelmintics. A trial involving 18 goats was conducted to confirm this. There was a significant (P < 0.01) reduction in worm burdens in goats given levamisole, but this was not so for those animals given albendazole, fenbendazole, oxfendazole and mebendazole (P > 0.05).