Climate change and the resurgence of malaria in the East African highlands

Abstract

The public health and economic consequences of Plasmodium falciparum malaria are once again regarded as priorities for global development. There has been much speculation on whether anthropogenic climate change is exacerbating the malaria problem, especially in areas of high altitude where P. falciparum transmission is limited by low temperature. The International Panel on Climate Change has concluded that there is likely to be a net extension in the distribution of malaria and an increase in incidence within this range. We investigated long-term meteorological trends in four high-altitude sites in East Africa, where increases in malaria have been reported in the past two decades. Here we show that temperature, rainfall, vapour pressure and the number of months suitable for P. falciparum transmission have not changed significantly during the past century or during the period of reported malaria resurgence. A high degree of temporal and spatial variation in the climate of East Africa suggests further that claimed associations between local malaria resurgences and regional changes in climate are overly simplistic.

Observations: Cryosphere

“…They also report, after Hastenrath (2001), "there is no evidence of a sudden change in temperature [in East Africa] at the end of the 19th century," as confirmed by King'uyu et al (2000) and Hay et al (2002), who show East African twentieth century temperature records show diverse trends and do not exhibit a uniform warming signal.…”

The potential effects of climate change on malaria transmission in Africa using bias-corrected regionalised climate projections and a simple malaria seasonality model

“…Epstein et al 1998;Pascual et al 2008;Omumbo et al 2011). Patz et al (2002) found that the methods used by Hay et al (2002a) were incorrect. Recently, Omumbo et al (2011) used atmospheric measurements from the Kenyan Highlands and pointed out that the climate conditions remain a potential driver of malaria.…”

A changed climate in Africa?

“…As an alternative, researchers have used so-called 'climate surfaces' -maps interpolated from these sparse data. But these surfaces often provide only a coarse representation of climate, and their usefulness in relation to the scale of the malaria data has been open to question [10][11][12] . To eliminate this mismatch, Small et al 3 used a malaria transmission index calculated directly from the interpolated climate data.…”