Spatio-temporal patterns of malaria in Nepal from 2005 to 2018: A country progressing towards malaria elimination

Abstract

Nepal aims to eliminate malaria by 2026. This study analyzed district-level spatio-temporal patterns of malaria in Nepal from 2005 to 2018, following the introduction of Long-Lasting Insecticidal Nets (LLINs) for vector control intervention. The spatial variation in a temporal trend (SVTT) method in SaTScan was used to detect significantly high or low temporal trends of five malaria indicators: Indigenous, Imported, PV (Plasmodium vivax), PF (Plasmodium falciparum), and Total Malaria; results were mapped as clusters with associated trends. Spatial clusters of increasing malaria were found for all five indicators. Indigenous Malaria increased 113.71% in a cluster of three previously non-endemic mountainous districts. The most prominent cluster of Imported Malaria increased by 156.22%, and included the capital, Kathmandu. While some clusters had decreasing malaria, the rate of decrease in clusters was lower than outside the clusters. Overall, malaria burden is decreasing in Nepal as the country progresses closer to the elimination deadline. However, spatial clusters of increasing malaria, and clusters of lower rates of decreasing malaria, point to a need to focus vector control interventions on these clusters.

Keywords: Control intervention; Malaria elimination; Nepal; Spatial variation; Spatio-temporal pattern; Temporal trend.