Malaria Elimination Campaigns in the Lake Kariba Region of Zambia: A Spatial Dynamical Model

November 23, 2016

Abstract: 

Background
Malaria is a vector-borne parasitic disease affecting millions of people worldwide, with Plasmodium falciparum still causing over 400,000 deaths per year [1]. Recent escalation in vector control has greatly reduced global burden and brought many regions close to elimination [2]. In some settings,mass drug campaigns have been an effective tool for depleting the human infectious reservoir and breaking the cycle of transmission, although the effectiveness of such campaigns has been mixed

Methods
During each of the 2012 and 2013 dry seasons (June-November) in Southern Province, Zambia, three large-scaleMTAT rounds were undertaken [7]. Individuals were visited at theirhomes in a full community census and, following consent, administered RDTs. Test-positive individuals were treated with the antimalarial drug artemether-lumefantrine (AL), of which the first dose was directly observed.During each MTAT round, RDT results were geo-tagged by household location. Information was collected on household demographics, ITN usage, recent fevers, and recent drug treatments.

Results
A high-resolution spatial model of twelve health facility catchment areas (HFCAs) in the Lake Kariba region was configured based on village-scale clusters of households and ITN usage, MTAT coverage, casemanagement, and human migration rates derived from the surveys conducted in 2012–13 (Fig 1). Malaria transmission was modeled within each cluster, where vector populations were driven by cluster-specific climate data and local abundance of larval habitats. Preliminary entomological data indicated that both Anopheles arabiensis and Anophelesfunestus are present in the study area (personal communication with Javan Chanda), with arabiensis biting rates highest between January and April during the warm rainy season while funestus peaks in September at the beginning of the hot dry season. Relative abundances of arabiensis and funestus govern the seasonality of malaria transmission, while absolute abundances determine the intensity.

Fig 1 Households in the Lake Kariba region of Southern Province, Zambia, are clustered into village-scale simulation constructs within twelve health facility catchment areas.