Impact of climate change on global malaria distribution

Abstract

Malaria is an important disease that has a global distribution and significant health burden. The spatial limits of its distribution and seasonal activity are sensitive to climate factors, as well as the local capacity to control the disease. Malaria is also one of the few health outcomes that has been modeled by more than one research group and can therefore facilitate the first model intercomparison for health impacts under a future with climate change. We used bias-corrected temperature and rainfall simulations from the Coupled Model Intercomparison Project Phase 5 climate models to compare the metrics of five statistical and dynamical malaria impact models for three future time periods (2030s, 2050s, and 2080s). We evaluated three malaria outcome metrics at global and regional levels: climate suitability, additional population at risk and additional person-months at risk across the model outputs. The malaria projections were based on five different global climate models, each run under four emission scenarios (Representative Concentration Pathways, RCPs) and a single population projection. We also investigated the modeling uncertainty associated with future projections of populations at risk for malaria owing to climate change. Our findings show an overall global net increase in climate suitability and a net increase in the population at risk, but with large uncertainties. The model outputs indicate a net increase in the annual person-months at risk when comparing from RCP2.6 to RCP8.5 from the 2050s to the 2080s. The malaria outcome metrics were highly sensitive to the choice of malaria impact model, especially over the epidemic fringes of the malaria distribution.global climate impacts | disease modeling | uncertainty H ealth priorities vary between countries and also change significantly over time. One of the factors that governments are concerned with preparing for over decadal timescales is the potential impact that environmental and climate change may have on health and welfare (1, 2). These impacts are complex and multifaceted and include the potential for changing climate to alter in both time and space the burden of vector-borne diseases, including malaria.Malaria causes a significant burden of disease at the global and regional level (3). Malaria is a mosquito-borne infectious disease caused by parasitic protozoans of the genus Plasmodium (vivax, malariae, ovale, knowlesi, and falciparum) and is transmitted by female mosquito vectors of the Anopheles species. The spatial limits of the distribution and seasonal activity are sensitive to climate factors, as well as the local capacity to control the disease. In endemic areas where transmission occurs in regular long seasons, fatality rates are highest among children who have not yet developed immunity to the disease. In epidemic areas where malaria transmission occurs in short seasons or sporadically in the form of epidemics it is likely to cause severe fatalities in all age categories. Following the Global Malaria eradication program launched by the ...

Towards the implementation of malaria elimination policy in South Africa: the stakeholders’ perspectives

“…While there is no denial that over the years malaria morbidity and mortality have been drastically reduced in South Africa [13,15] and elsewhere in the world [1,2], informants shared mixed views as to what led to these reductions. Some claimed that these achievements were as a result of effective malaria control interventions [5,13,35].…”

“…Some claimed that these achievements were as a result of effective malaria control interventions [5,13,35]. Others attributed the successes to changes in the climate, as implicated in other studies [1]. The recent intermittent resurgences of malaria in the least expected areas are not only concerning, but raise questions about the understanding of malaria epidemiology in South Africa.…”

“…Others believed though that the key drivers of the policy formulation process were high-level international organisations, such as the WHO and the SADC [10], and South Africa was, to some extent, politically pressured to see the policy through to implementation [11]. Two other politically sensitive issues emerged, namely [1]: the need for strong cross-border collaboration with sensitivities emanating from the recent xenophobic attacks in the country, and [2] the delay in the registration of a transmission-blocking drug called Primaquine. The informants proposed a political intervention to ensure the timeous registration of the drug by the MCC, so that the elimination mandate is not hindered.…”

“…Achievements in the fight against malaria over the past decade are well documented [1]. Despite these gains, malaria continues to be a leading cause of morbidity and mortality in the world, with approximately 214 million annual cases and 438,000 deaths in 2015 [2].…”

“…Approximately 663 million clinical cases were averted in endemic areas of Africa between the years 2000 and 2015 [4]. Between 2000 and 2010, the global malaria incidence and deaths decreased by 17% and 26%, respectively [1,5]. In endemic areas of Africa, the incidence of clinical cases decreased by 40% between 2000 and 2015 [4].…”