[Current strategies for the prevention of malaria]

Abstract

Two billion of persons live in regions where endemic malaria prevails or has reappeared. An estimated on hundred million infected individuals per year have been reported around the world. In front of this alarming situation, the diversity and even the incoherence of the currently proposed prophylactic regimens confuses the therapists and renders difficult the adoption of an efficacious strategy. The extension and gravity of drug resistance of P. falciparum and the withdrawal of anti-vectorial campaign constitute two reasons for the present recrudescence of malaria. The preventive strategies in 1990 are based on: rehabilitation of anti-vectorial campaign particularly against nocturnal mosquito bites, applicable to all, everywhere and at all times, by the means of individual and collective measures and mostly by impregnated nets; chemoprophylaxis for which two situations should be distinguished: the non immune traveler leaving for a short period (inferior or equal to 3 months) to an endemic area: individuals living permanently or for long periods in tropical regions. Prevention for short stays In low risk transmission zone (North Africa, Mexico, large cities of South East Asia) whatever the duration, suppression of chemoprophylaxis is acceptable. In high risk transmission zone, three strategies exist according to the intensity and frequency of drug resistance: zone 1 (P. vivax or drug sensitive P. falciparum): chloroquine at a dose of 100 mg/day for adults (1.5 mg/kg/day for children) 6 days out of 7, from the day of departure trough the whole stay and for one month after the return, is still efficacious; zone 2 (moderate frequency of drug resistance): protection is again ensured by chloroquine only, as in zone 1, or better than that by the association of chloroquine 300 mg once a week and proguanil 200 mg/day (3 mg/kg/day for children). The side effects of mefloquine and the risk of generation drug resistance argue against its general use in this zone particularly in West Africa. In one year, we have already observed three chemoprophylactic failures with mefloquine in individuals returning from this region; zone 3 (high frequency of drug resistance and multiresistance): mefloquine, if well tolerated is justified in weekly intake. In case of contraindications or intolerance to mefloquine, which are becoming more frequent, no substitution for that chemoprophylactic regimen is presently available. In view of these facts, indications, contraindications and posologies of mefloquine should be reviewed to better profit from the remarkable characteristics of this antimalarial. Mefloquine should only be prescribed (excluding curative treatment) for chemoprophylaxis of short stays in zone 3. Some contraindications of this drug should be maintained (pregnant women) or made relative (treatment with B-blockers and in the absence of pediatric studies, children weighing less than 15 kg).(ABSTRACT TRUNCATED AT 400 WORDS)