Malaria control in Botswana, 2008–2012: the path towards elimination

Abstract

BackgroundBotswana has made substantial progress towards malaria elimination across the country. This work assessed interventions and epidemiological characteristics of malaria in Botswana, during a period of decreasing transmission intensity.MethodsNational passive malaria surveillance data for five years (2008–2012) were analysed. A district-level, random effects model with Poisson regression was used to explore the association between malaria cases and coverage with long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS). Malaria cases were mapped to visualize spatio-temporal variation in malaria for each year.ResultsWithin five years, a reduction in malaria prevalence (approximately 98%) and number of deaths (12 to three) was observed. Between 2008 and 2012, 237,050 LLINs were distributed and 596,979 rooms were sprayed with insecticides. Coverage with LLINs and IRS was not uniformly distributed over the study period and only targeted the northern districts with a high malaria burden. The coverage of IRS was associated with a reduction in malaria cases.ConclusionsBotswana has made significant strides towards its goal of country-wide elimination of malaria. A major challenge in the future will be prevention and management of imported malaria infections from neighbouring countries. In order to accurately monitor progress towards the elimination goal, the malaria control programme (NMP) should strengthen the reporting and capturing of data at household and individual level. Systematic, periodic operational research to feedback the NMP will help to guide and achieve elimination.

Spatio-temporal distribution of malaria and its association with climatic factors and vector-control interventions in two high-risk districts of Nepal

“…Only LLINs is found to be associated with a decline of malaria incidence in the present study, which is consistent with findings from Bangladesh [ 24 ] Rwanda [ 33 ], and Zambia [ 34 ]. In contrast to findings of this study, malaria incidence was associated with IRS coverage only in Botswana [ 22 ]. These findings imply that vector control interventions with a low coverage, or those that are focussed on selected VDCs only, cannot break down malaria transmission in VDCs or districts bordering malaria-endemic areas because the presence of vectors, a suitable climate and the continuous import of malaria cases facilitate the transmission cycle.…”

“…Annual malaria incidence at the VDC level was analysed independently for spatial clustering (or hotspots) using the Getis-Ord Gi* statistic [ 21 – 23 ] in the Arc GIS software version 10 (ESRI, Redland, CA, USA). This statistic reflects whether differences between the local mean (i.e., the incidence for a VDC and its nearest neighbouring VDC within a district) was significantly different from the global mean (i.e., the overall incidence of all VDCs for that particular district) [ 22 , 24 , 25 ]. A statistically significant positive z-score value shows a hotspot for high incidence rates while a statistically significant negative z-score value for a VDC specifies local spatial clustering of low incidence rates [ 22 , 24 – 26 ].…”

“…This statistic reflects whether differences between the local mean (i.e., the incidence for a VDC and its nearest neighbouring VDC within a district) was significantly different from the global mean (i.e., the overall incidence of all VDCs for that particular district) [ 22 , 24 , 25 ]. A statistically significant positive z-score value shows a hotspot for high incidence rates while a statistically significant negative z-score value for a VDC specifies local spatial clustering of low incidence rates [ 22 , 24 – 26 ]. Two separate cluster analysis was performed and presented with one using all malaria cases and one with just imported malaria cases.…”

Demonstration of successful malaria forecasts for Botswana using an operational seasonal climate model

“…Interventions have continued in Botswana, from DDT spraying in the 1950s to the current program of bed net distribution, indoor residual spraying and winter biolarviciding, alongside passive surveillance (Chihanga et al 2013). Incidence forecasts can contribute to the surveillance program and guide the allocation of financial and material resources.…”

Geospatial Technology: A Tool to Aid in the Elimination of Malaria in Bangladesh

“…Countries engage in malaria control [33][34][35][36] and elimination [37] may learn from Bangladeshi experiences. Spatial analytical studies have shown a higher incidence of malaria in areas adjacent to these international borders [26].…”