SciDev.Net

Resurgences of malaria in East Africa are linked to rising temperatures over the past few decades, according to a new analysis.

The findings in this week's issue of Nature challenge the results of a study published earlier this year. The authors of the first study found no significant connection between climate change and malaria prevalence in the region (see Climate change and malaria growth not linked), and concluded that something other than global warming must have fuelled the rise of malaria in the past two decades, such as the growth of drug resistance.

But an international team of scientists now says that global warming and malaria prevalence are indeed linked, and that the original study's conclusions were flawed by its "inappropriate use" of climate data. They argue that the study crucially ignored temperature variability and that the data collected did not accurately reveal climate trends for specific locations.

"Weather data is particularly sparse in East Africa, and the climate database used was originally created to pool information for analysis over large geographic areas," says the lead author of the new analysis, Jonathan Patz from Johns Hopkins Bloomberg School of Public Health. "There is potential, therefore, for reaching spurious conclusions when using such climate data to study diseases at the local level."

But the authors of the first study, led by Simon Hay of the University of Oxford, United Kingdom, stand by their conclusions. "Rather than climate change, variations in environmental, social and epidemiological factors are more plausible for the malaria resurgences," they respond. "Evidence against the epidemiological significance of climate change in the recent malaria resurgences in Africa is mounting and remains unmatched by any contrary evidence."

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Link to analysis by Patz et al and response by Hay et al