Comparison of oral ivermectin vs. lindane lotion 1% for the treatment of scabies.

BACKGROUND: Scabies is a common parasitic infestation that is an important public-health problem in many resource-poor regions. It is commonly treated with the insecticides ivermectin and permethrin. AIM: To compare the efficacy and safety of oral ivermectin vs. lindane lotion 1% for the treatment of scabies. METHODS: In total, 148 patients with scabies were enrolled, and were randomized into two groups: the first group received a single dose of oral ivermectin 200 µg/kg body weight, and the second group were treated with two applications of topical lindane lotion 1%, with a 1-week interval between applications. Treatment was evaluated at intervals of 2 and 4 weeks, and if there was treatment failure at the 2-week follow-up, treatment was repeated. RESULTS: A single dose of ivermectin provided a cure rate of 60.8% at the 2-week follow-up, which increased to 89.1% at the 4-week follow-up. after crossing over to the lindane lotion 1% group. Treatment with two applications of lindane lotion 1%, with a 1-week interval between them, was effective in 47.2% of patients at the 2-week follow-up, which increased to 72.9% at the 4-week follow-up after this treatment was repeated. CONCLUSIONS: A single dose of ivermectin was as effective as two applications of lindane lotion 1% at the 2-week follow-up. After repeat treatment, ivermectin was superior to lindane lotion 1% at the 4-week follow up. The delay in clinical response with ivermectin suggests that it may not be effective against all the stages in the life cycle of the parasite.

The effect of the Fusarium metabolite beauvericin on electromechanical and -physiological properties in isolated smooth and heart muscle preparations of guinea pigs.

The electromechanical and -physiological effects of beauvericin were studied in isolated smooth and heart muscle preparations of the guinea pig. Beauvericin concentration-dependently decreased the force of contraction in precontracted (60 mM KCl) terminal ilea with an IC50 of 0.86 microM, and in electrically stimulated (1 Hz) papillary muscles with an IC50 of 18 microM. This negative inotropic effect in papillary muscles was antagonised in a non-competitive way by increased extracellular calcium concentrations. Spontaneous activity in right atria was affected at concentrations > 10 microM beauvericin. The negative chronotropic effect was less pronounced than the negative inotropic effect. In action potentials of electrically driven (1 Hz) papillary muscles, 10 microM beauvericin significantly decreased membrane resting potential until unexcitability of the preparation occurred. Despite depolarisation of the membrane the maximum rate of rise of the action potential was not changed. The action potential duration was shortened, but the decrease was only significant at times to 20% and 50% repolarisation. These data, derived from the electrophysiological experiments, not only imply an effect on the calcium current as suggested by the effects on contractility, but also an interaction with the sodium inward and potassium outward currents.

Sustainability of pyrethroid-impregnated bednets for malaria control in Afghan communities.

Between 1992 and 1995 a series of studies was undertaken to assess the long-term suitability of pyrethroid-impregnated bednets (PIBs) for malaria control in Afghan refugee communities in two villages in North-West Frontier Province, Pakistan. During 1992, 86% of bednet owners volunteered to have their bednets re-impregnated, and a further 15% of families purchased nets at two-thirds of cost price. From 1992 onwards, 27% of the villagers returned to Afghanistan, and annual house spraying campaigns were introduced to protect those still resident but sleeping without bednets. Within 3 years, these campaigns, together with PIBs, reduced the annual incidence of malaria by 87%, from 597 to 78 cases per 1000 population. Nevertheless, 65% of resident families continued to re-impregnate their nets annually with permethrin. To assess whether PIBs were still being used and were still protective, in view of these reduced transmission rates, we carried out a case--control study in 1994 on febrile or otherwise symptomatic patients presenting at village health centres. Comparison of the slide-positivity rates of PIB users and those without bednets showed that regular usage reduced the odds of contracting falciparum and vivax malaria to 0.22 (95% confidence interval (CI): 0.09-0.55) and 0.31 (95% CI: 0.19-0.51), respectively. There was no evidence of a sex- or age-bias in bednet use or in protective effect. The results indicate that a community-based PIB programme is an appropriate malaria control measure in areas where management or security problems make traditional house-spraying campaigns impossible. A relevant finding for those involved in the monitoring of bednet distribution projects is that the local coverage of bednets and the local impact on malaria, even when introduced to remote areas, can be estimated very cheaply by health centre microscopists who simply catalogue blood film diagnoses according to patients' bednet use practices.

PIP: A series of studies was conducted between 1992 and 1995 to assess the long-term suitability of pyrethroid-impregnated bednets (PIBs) in controlling malaria in Afghan refugee communities in two villages in North-West Frontier Province, Pakistan. During 1992, 86% of bednet owners volunteered to have their bednets re-impregnated, and an additional 15% of families bought bednets at two-thirds of cost. From 1992 onwards, 27% of the villagers returned to Afghanistan where annual house spraying campaigns were introduced to protect those still resident but sleeping without bednets. Within 3 years, those campaigns, together with PIBs, reduced the annual incidence of malaria by 87%, from 597 to 78 cases per 1000 population. 65% of resident families continued to reimpregnate their nets annually with permethrin. A case-control study conducted in 1994 on febrile or otherwise symptomatic patients presenting at village health centers found that the regular use of bednets reduced the odds of contracting falciparum and vivax malaria to 0.22 and 0.31, respectively. No evidence was found of sex or age bias in bednet use or in protective effect.