The study was conducted using existing serum samples from inhabitants of Antananarivo who had been enrolled in February 2004 for a study on hepatitis C. The history of contact between humans and Plasmodium falciparum was examined by measuring seroprevalence in a representative population from the urban zone, to identify factors associated with exposure to malaria. The mosaic nature of the Antananarivo environment exposes the inhabitants of certain zones to the risk of malaria outbreaks. Imported cases outnumber cases of indigenous malaria, and studies have shown only low levels of indigenous malaria transmission. About 80% of the confirmed cases had travelled outside the city to areas exposed to malaria in the weeks preceding the survey, the remaining 20% of cases being cases of indigenous malaria due to local transmission. Two surveys carried out in Antananarivo in 2003 showed, by biological examinations, that less than 2% of all cases of fever were confirmed to be malaria. New epidemic episodes appeared in the middle of the 1980s, causing several tens of thousands of deaths. At the beginning of the 1980s, Anopheles funestus reappeared in the Central Highlands of Madagascar, from which it had disappeared in the 1950s. Some of the seedier districts in the middle of town have zones that flood easily, favouring mosquito breeding. The Antananarivo plain is covered by vast areas of irrigated rice fields, which are potential breeding sites for malaria vectors. The city and its surroundings include 1,700,000 inhabitants (2001 census), corresponding to about 10% of the national population.
Antananarivo, the capital of Madagascar, is located on hills in the middle of the Central Highlands, at an altitude of between 1,200 and 1,400 m.
0 kommentar(er)
