[Drug resistance and therapeutic strategy]

In Madagascar, Plasmodium falciparum resistance to chloroquine was clinically suspected in 1975 by Goasguen and demonstrated in 1981 by Arronson et al. Since then, many studies were conducted throughout the island, in the North, South, East and West, on the high Plateau and on the coasts. Two methods were used, including an in vivo method similar to the therapeutic standard protocol of the WHO, and an in vitro method employing the semi-microtest of Le Bras and Deloron. From 1982 to 1986, the 291 in vivo tests performed showed that 20% of the strains were of the types R1 or R2 (SR1 included). From 1987 to 1994, of the 621 in vivo tests performed, 369 (59.4%) of the cases responded to treatment. The deterioration of the situation observed in 1988 (Lepers et al.) seemed to be stabilized (Ringwald et al.). No strain of the type R3 was found. In conclusion, we report the absence of strain type R3 and also the clinical efficacy of chloroquine. The action of chloroquine was spectacular on the fevers and there was remarkable reduction of the parasitaemia. Thus, for treating outbreaks of simple malaria in Madagascar, chloroquine remains the best choice if it is administered at an efficacious dose.