The impact of urbanization on malaria infection rate and parasite density in children in the municipality of Yopougon, Abidjan (Cote d'Ivoire)

From September 23-30, 2005, we conducted a cross-sectional study in six townships of Yopougon, a municipality of Abidjan. These townships were grouped in three levels of urbanization (village, precarious township, and residential township). The main objective of this survey was to determine the impact of urbanization on the malaria infection (parasite) rate and parasite density, and their consequences on the heterogeneity of malaria transmission in urban Abidjan. Specifically we compared these rates in all three urbanization levels, selecting two townships for each level to take environmental specificities observed from previous data into account. The study included 400 households per township. All children younger than 5 years in these households were included. Thick and thin blood smears were taken for each child on slides, and each slide was examined by microscope after staining. The malaria infection rate was 21.8%, indicating mesoendemic malaria. Its distribution varied significantly between the three urbanization levels. Malaria parasite densities also varied significantly between them. These results confirm the involvement of urbanization in the heterogeneity of malaria transmission in the city of Abidjan.