Climate Suitability for Stable Malaria Transmission in Zimbabwe Under Different Climate Change Scenarios

Stanford University, Stanford, California, United States
Climatic Change (Impact Factor: 3.43). 12/2005; 73(3):375-393. DOI: 10.1007/s10584-005-6875-2


Climate is one factor that determines the potential range of malaria. As such, climate change may work with or against efforts
to bring malaria under control. We developed a model of future climate suitability for stable Plasmodium falciparum malaria transmission in Zimbabwe. Current climate suitability for stable malaria transmission was based on the MARA/ARMA
model of climatic constraints on the survival and development of the Anopheles vector and the Plasmodium falciparum malaria parasite. We explored potential future geographic distributions of malaria using 16 projections of climate in 2100.
The results suggest that, assuming no future human-imposed constraints on malaria transmission, changes in temperature and
precipitation could alter the geographic distribution of malaria in Zimbabwe, with previously unsuitable areas of dense human
population becoming suitable for transmission. Among all scenarios, the highlands become more suitable for transmission, while
the lowveld and areas with low precipitation show varying degrees of change, depending on climate sensitivity and greenhouse
gas emission stabilization scenarios, and depending on the general circulation model used. The methods employed can be used
within or across other African countries.

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Available from: John Weyant, Jul 08, 2015
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    • "Mordecai et al. (2013) conclude that as temperature increases due to climate change, vector control will likely become more important, difficult and expensive in temperate areas, but some war areas may simply become too hot to support malaria. Ebi et al. (2005) assert that Zimbabwean highlands will become climatologically favourable to malaria by 2050. A trade-off exits between fast parasite development and high mosquito mortality at temperature and rainfall ranges above or below optimum, such that high temperature does not always increase transmission. "
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    ABSTRACT: Malaria in Limpopo Province of South Africa is shifting and now observed in originally non-malaria districts, and it is unclear whether climate change drives this shift. This study examines the distribution of malaria at district level in the province, determines direction and strength of the linear relationship and causality between malaria with the meteorological variables (rainfall and temperature) and ascertains their short- and long-run variations. Spatio-temporal method, Correlation analysis and econometric methods are applied. Time series monthly meteorological data (1998-2007) were obtained from South Africa Weather Services, while clinical malaria data came from Malaria Control Centre in Tzaneen (Limpopo Province) and South African Department of Health. We find that malaria changes and pressures vary in different districts with a strong positive correlation between temperature with malaria, r = 0.5212, and a weak positive relationship for rainfall, r = 0.2810. Strong unidirectional causality runs from rainfall and temperature to malaria cases (and not vice versa): F (1, 117) = 3.89, ρ = 0.0232 and F (1, 117) = 20.08, P < 0.001 and between rainfall and temperature, a bi-directional causality exists: F (1, 117) = 19.80; F (1,117) = 17.14, P < 0.001, respectively, meaning that rainfall affects temperature and vice versa. Results show evidence of strong existence of a long-run relationship between climate variables and malaria, with temperature maintaining very high level of significance than rainfall. Temperature, therefore, is more important in influencing malaria transmission in Limpopo Province.
    Full-text · Article · Dec 2014 · EcoHealth
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    • "Climate change could have significant consequences for regional stability (Miguel et al. 2004) – some notable hotspots being West Africa and the Nile Basin (Stern 2007). Scholars argue that a lack of knowledge , technology and present state fragility could undermine Africa's capabilities to deal with climate change (Brown et al. 2007; Brown & Crawford 2009), which is expected to severely impact the continent's economy (Collier et al. 2008), health (Chen et al. 2006; Hartmann et al. 2002; Pascual et al. 2006) and infrastructure (Myers 2002; McLeman & Smit 2004). "
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    ABSTRACT: The linkages between conflict, climate change and natural resources are increasingly acknowledged in academic and policy realms. Nowhere are these linkages more evident than in Africa, which is highly susceptible to violent conflict as a result of climate-related shocks. As resource scarcity intensifies, conflicts over high-value resources and those essential for livelihoods such as water and land may also increase, feeding into pre-existing patterns of insecurity, and exacerbating them. Mediation offers a promising tool for resolving conflicts over natural resources in a sustainable manner and oriented away from a zero-sum framework. Our understanding of how to mediate natural resource conflicts has increased, but putting this knowledge into practice remains a challenge. Enhancing mediation guidance and refining strategies for the implementation of such guidance as it relates to natural resources relies on bringing together the knowledge of a variety of experts, including scientists, social scientists and mediators. This Chapter briefly explores the risk of conflicts associated with climate change and natural resources. It then embarks upon an exploration of mediation strategies relevant to such conflicts as a tool of prevention and resolution, both in conflicts where natural resources are the major driver, and those where natural resources are addressed as a part of wider peace agreements at the political level between and within African nations.
    Full-text · Chapter · Jan 2014
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    • "Understanding how it may affect human health and disease is complex and requires a thorough understanding of links between present climate and disease (Epstein 2005). Links between climate and diseases with various modes of transmission (vector-, water-, food-, soil-, and airborne) have been identified (Colwell and Patz 1998; Epstein 2001), with the strongest associations being between climate and mosquitoborne diseases (Ebi et al. 2005; Rogers and Randolph 2000; Small et al. 2003). Although widely held as the world's most important arbovirus, only one review of potential climate change impacts on dengue virus (DENV) transmission has been published with a focus on tools currently used to establish climate– disease associations (Thai and Anders 2011). "
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    ABSTRACT: Climate influences dengue ecology by affecting vector dynamics, agent development, and mosquito/human interactions. While these relationships are known, the impact climate change will have on transmission is unclear. Climate-driven statistical and process-based models are being used to refine our knowledge of these relationships and predict the effects of projected climate change on dengue fever occurrence, but results have been inconsistent. We identify major climatic influences on dengue virus ecology and evaluate the ability of climate-based dengue models to describe associations between climate and dengue, simulate outbreaks, and project the impacts of climate change. We review the evidence for direct and indirect relationships between climate and dengue generated from laboratory studies, field studies, and statistical analyses of associations between vectors, dengue fever incidence, and climate conditions. The potential contribution of climate driven, process-based dengue models is assessed, and suggestions are provided to improve their performance. Relationships between climate variables and factors that influence dengue transmission are complex. A climate variable may increase dengue transmission potential through one aspect of the system, while simultaneously decreasing potential through another. This complexity may at least partly explain inconsistencies in statistical associations between dengue and climate. Process-based models can account for the complex dynamics but often omit important aspects of dengue ecology, notably virus development and interactions between host species. Synthesizing and applying current knowledge of climatic effects on all aspects of dengue virus ecology will help direct future research and enable better projections of climate change effects on dengue incidence.
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