Restoration of malaria control in the Madagascar highlands by DDT spraying

Abstract

The coastal areas of Madagascar have stable malaria like much of lowland tropical Africa. However the highlands (1000–1500 meters) had unstable seasonal Plasmodium falciparum malaria since its arrival in the 19th century when rice growing was introduced there. At the end of the French colonial era in the 1950s malaria and its main vector Anopheles funestus were suppressed to near or complete eradication in the highlands. This was achieved by spraying DDT mixed with tHCH in over a million houses and mass chemoprophylaxis of schoolchildren with chloroquine given 3 times per week at 2375 schoolchildren’s treatment centers. In Antananarivo province the percentage of positive blood slides was reduced from 25–35% in the late 1940s to 0.18% (6 positive among 3348 slides from children aged 2–10 years) in 1955. An. funestus which had been abundant resting in highland houses in the 1940s could not be found in the region in 1955.2 Some spraying continued and there were centers at which chloroquine was available until the late 1970s when these measures were regrettably abandoned. An. funestus crept back into the area between 1976 and the 1980s. A sporozoite positive individual was found in 1987 and a plea was then made for urgent introduction of control measures. (excerpt)