[Particularities and stratification of malaria in Madagascar]

The first factor is the malaria parasite, for which the species P. falciparum and P. vivax are important. Secondly, the transmission determines the disease stability and challenges the host's immunity. The third factor is the human host, consisting of people of both African and Asiatic origin, the latter of whom are more susceptible to P. vivax. Human activities such as cultivating rice fields are of paramount importance for the proliferation of the vectors. The vectors A. gambiae, A. arabiensis and A. funestus are very similar to those of the African continent. These vectors are not endemic on Madagascar, suggesting that they were recently introduced to the island where 95% of the fauna species are endemic. On the Plateau and in the South, the rice fields provide most of the breeding places for A. gambiae s.l. and A. funestus. Five epidemiological belts are found in Madagascar which are very similar to their analogs on continental Africa (fig. 1). These facies include the equatorial belt on the east coast and the tropical belt on the west coast north of Morondava, the Plateau belt analogous to the southern African continent, the southern Madagascar belt which is similar to the Sahelian areas, and finally the zones above 1,500m, which are essentially free of malaria. The first two facies have a stable type of malaria, and in the following two, malaria is unstable. These areas include the Plateau, the area of the severe epidemics which occurred between 1985 and 1988 with more than 50,00 deaths. Malaria control is based on a variety of strategies to respond to the epidemiological heterogeneity of the disease. Spraying within the homes with DDT, used on the Plateau after 1988, was and still is very successful.