Evidence of spatial clustering distribution patterns of malaria in Epe, Lagos, Nigeria

Abstract

Investigation of the spatial distribution patterns of malaria with the goal of detecting intense transmission areas and clustering is prerequisite to planning an effective targeted malaria intervention. Parasitological sampling was done in settlements in Epe and Orimedu, Lagos, Nigeria. Blood samples were collected from 360 participants with georeferenced residences, selected through multistage systematic sampling technique. Each study area was delineated into 3 Malaria Risk Zones (MRZs), namely; Very High (V-MRZ), High (H-MRZ) and low (L-MRZ), according to distances of 500 m, 1000 m and 1500 m respectively away from perennial water bodies. Clustering and Outlier analysis was carried out to generate predictive malaria risk maps. Overall malaria prevalence was 32.2%., being significantly higher in Orimedu (52.6%) than Epe (47.4%), p < 0.05. Prevalence was 28.2%, 32.0% and 50.0% in the VH-MRZ, High-MRZ and L-MRZ respectively in Epe. H-MRZ accounted for the highest prevalence (66.7%), in Orimedu, followed by the V-MRZ (32.8%) while the L-MRZ was uninhabited. Malaria clusterings were detected in Uraka, Iberikodo and Sagidan settlements in Epe (Moran’s Index = 0.62, p < 0.05) but not in Orimedu. The multiple distinct malaria risk zones coupled with the characteristic steep topography may be responsible for forcing malaria to localize and cluster in Epe compared to Orimedu.