Malaria and Climate Change

Today is World Malaria Day, which seems as good a time as any to revisit the objective of the organisation with whom I worked last summer. So too, with this year’s Earth Day only recently marked, Roll Back Malaria’s Action and Investment to Defeat Malaria, 2016-2030 publication identifies the ever relevant climate related goal: ‘given that climate change is predicted to increase the range and intensity of malaria transmission, plans to mitigate the effects of climate change are likely to include an increased commitment to controlling and eliminating malaria, and vice versa’.

Weather and climate are major determinants of malaria. The Intergovernmental Panel on Climate Change has concluded that changes in temperature and rainfall will affect the natural habitats of mosquitoes, changing the prevalence of the vector or prolonging transmission seasons (or both) in some areas, and potentially exposing new regions and populations to malaria and other vector-borne diseases [1].

Temperature rises (associated with current rates of carbon emission) of just 2-3 degrees Celsius will increase the number of people at risk of malaria by up to 5 per cent, representing several hundred million people [2]. Further, a World Bank report indicates that by 2050, climate change might threaten some previously unexposed regions of South America, sub-Saharan Africa and China causing a 50 per cent higher probability of malaria transmission[3].

We can turn to country cases to better narrate these statistics and to outline the continuing challenges. A study published in 2014 in the Open Journal of Ecology assessed patterns of climate variables and malaria cases in two ecological zones of Ghana. The researchers suggested that a better understanding of the relationship between rainfall patterns and malaria cases is required for effective climate change adaptation strategies involving planning and implementation of appropriate disease control interventions.

By analysing climatic data and reported cases of malaria spanning a period of eight years (2001 to 2008) from two ecological zones in Ghana (Ejura and Winneba in the transition and coastal savannah zones respectively) they determined the association between malaria cases, temperature and rainfall patterns and the potential effects of climate change on malaria epidemiological trends. The results suggest maximum temperature as a better predictor of malaria trends than minimum temperature or precipitation, particularly in the transition zone.

Climate change effects on malaria caseloads seem multi-factorial. For effective malaria control, interventions could be synchronized with the most important climatic predictors of the disease for greater impact. By comparison, research in Nigeria published last year in the American Journal of Climate Change explored the relation between climate and epidemiology of malaria in the  Port Harcourt Region. The study examines the effect of climate on the occurrence of malaria in this region by matching data from the national meteorological service and hospital records to conclude that the prevalence of malaria is significantly dependent on the increase in rainfall and temperature and recommend regular clearing of drains and the surrounding environment combined with distribution of bednets.

So, what else can be done? The adoption and implementation of a multisectoral approach to defeating malaria remains a priority, with third tier government engagement needed to take the agenda forward. As ever, these narratives and burdens should not solely be addressed on the day in the calendar year in which they are officially marked, but remain continuing hurdles to improved health globally.

 

References:

[1] Further Reading: http://www.rollbackmalaria.org/about/multisectoral-action-framework/library [Environment and Climate]

[2] Appendix B, Action and Investment to defeat Malaria 2016-2030, June 2015.

[3] The Postdam Institute for Climate Impact Research and Climate Analytics, ‘Turn-down the Heat – Why a 4 degree Warmer World Must be Avoided,’ International Bank for Reconstruction and Development and World Bank, Washington, DC, 2012.

Image Credit: Fabian Biasio, WorldMalariaDay

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