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Malaria epidemics in the highlands of East Africa garner significant research attention, due, in part, to their proposed sensitivity to climate change. In a recent article, Zhou et al. claim that increases in climate variance, rather than simple increases in climate mean values, have had an important role in the resurgence of malaria epidemics in the East African highlands since the early 1980s. If proven, this would be an interesting result but we believe that the methods used do not test the hypothesis suggested.

The impact of human activities on the principles and processes governing the arrival, establishment and spread of exotic pathogens is illustrated by vector-borne diseases such as malaria, dengue, chikungunya, West Nile, bluetongue and Crimean–Congo haemorrhagic fevers. Competent vectors, which are commonly already present in the areas, provide opportunities for infection by exotic pathogens that are introduced by travel and trade. At the same time, the correct combination of environmental conditions (both abiotic and biotic) makes many far-flung parts of the world latently and predictably, but differentially, permissive to persistent transmission cycles. Socioeconomic factors and nutritional status determine human exposure to disease and resistance to infection, respectively, so that disease incidence can vary independently of biological cycles. [ABSTRACT FROM AUTHOR]

Investigates the interrelation of climatic change with the resurgence of malaria in the East African highlands. Factors contributing to the Plasmodium falciparum transmission; Trend of monthly and annual meteorological variables in the highlands; Use of augmented Dickey-Fuller test in analyzing the meteorological variables.

In our study we did not address the impact of predicted climate change on malaria incidence because a complete global assessment is reported elsewhere. Regarding the climate surfaces we used, the data set has superior spatial resolution compared with other data sets of similar temporal extent, and has been used to quantify climate change across Africa at 0.5 × 0.5° spatial resolution (although the resulting maps are smoothed to emphasize regional changes). It is inconsistent to assert that these same data are insufficient to demonstrate a lack of climate change. [ABSTRACT FROM AUTHOR]

Climate has a significant impact on malaria incidence and we have predicted that forecast climate changes might cause some modifications to the present global distribution of malaria close to its present boundaries. However, it is quite another matter to attribute recent resurgences of malaria in the highlands of East Africa to climate change. Analyses of malaria time-series at such sites have shown that malaria incidence has increased in the absence of co-varying changes in climate. We find the widespread increase in resistance of the malaria parasite to drugs and the decrease in vector control activities to be more likely driving forces behind the malaria resurgence. [Copyright &y& Elsevier]