Low autochtonous urban malaria in Antananarivo (Madagascar)

Two cross-sectional surveys in 43 health centres in Antananarivo in February 2003 (rainy season) and in July 2003 (dry season) were conducted. Consenting clinically suspected malaria patients with fever or history of fever in the past 48 hours were included. Malaria rapid diagnostic tests and microscopy were used to diagnose malaria. Basic information was collected from patients to try to identify the origin of the infection: autochthonous or introduced.In February, among 771 patients, 15 (1.9%) positive cases were detected. Three malaria parasites were implicated: Plasmodium. falciparum (n = 12), Plasmodium vivax (n = 2) and Plasmodium. ovale (n = 1). Only two cases, both P. falciparum, were likely to have been autochthonous (0.26%). In July, among 739 blood smears examined, 11 (1.5%) were positive: P. falciparum (n = 9) and P. vivax (n = 2). Three cases of P. falciparum malaria were considered to be of local origin (0.4%).This study demonstrates that malaria cases among febrile episodes are low in Antananarivo and autochthonous malaria cases exist but are rare.There is a hundred year-old history of control of malaria in African urban enviroment [1]. However, increasing attention is being devoted to this issue as a result of the rapid growth of cities and the fact that by 2025, more than 50% of the people in Africa are expected to be living in urban centres [2]. Despite its broad usage, the word 'urban' has an amazingly varied set of definitions. Most studies investigating the health consequences of urbanization employ ecological and cultural context comparisons of individuals living in urban versus rural environments [3-7]. There is no simple association between urbanicity and health [6], but the rapid increase of the world's urban population has major implications for the transmission and epidemiology of malaria and other vector-borne diseases [8,9].In most countries of sub-Saharan Africa, malaria transmission is generally intense in rural areas. In contrast, mal