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No link between malaria and global warming

A line drawing of a mosquito that transmits malaria (Anopheles gambiae), dorsal view. Date: 1999
Un moustique (WHO/TDR/Davies)

The increase in the prevalence of malaria in Kenya, Uganda, Rwanda and Burundi is not linked to global warming, says the scientific journal, Nature.

In an article published on Thursday, Simon Hay of the University of Oxford said drug resistance or the failure of health-care systems to keep pace with population growth were more likely culprits for malaria’s rise in eastern Africa. These should be the focus of public-health efforts, he urged.

"Drawing simplistic links between global warming and local disease patterns could lead to mistaken policy decisions," Hay’s team of researchers was quoted as saying.

"There’s been some terrible bandwagon-jumping and misdirection of resources that could be spent learning how to control mosquito-borne disease," Nature quoted Paul Reiter, an expert in insect-borne diseases at the Harvard School of Public Health, as saying. "We urgently need to cool down the rhetoric and start to look objectively at what the factors behind their recent resurgence are."

Malaria kills between one and two million Africans per year. In the regions on which the study focused, its incidence has risen sharply over the past two decades, in some cases more than fivefold, according to Nature.

Through computer simulations of the weather patterns of four upland regions, respectively in Kenya, Uganda, Rwanda and Burundi, between 1911 and 1995, Hay’s team established that there had been no significant climatic changes. Upland regions were chosen as they are more sensitive to climactic changes.

"The climate hasn’t changed, therefore it can’t be responsible for changes in malaria," said Hay.

However, Jonathan Patz, who studies climate’s relationship with health at John Hopkins University in Baltimore, disputes the findings, according to Nature. He said warming trends were affecting Africa, and the fact that Hay’s team had considered climate over a much longer period than that over which it had studied disease patterns could have "confused" its analysis.

"I think there’s a mismatch between the results and the strong conclusions of this paper," Patz said, adding that whether climate change influenced disease remained unclear.

Malaria was eliminated from the US and most of Europe during the first half of the 20th century as a result of changes in land use, agricultural practices and house construction, and targeted vector control.

With the development of the DDT insecticide, a global eradication programme was launched in the 1950s and 1960s, which was initially highly successful in countries such as India, Sri Lanka and the former Soviet Union. This success was not sustained, largely due to high costs and growing resistance to the insecticide on the part of the vectors.

On the other hand, no sustained efforts were made to control the disease in sub-Saharan African.

The failure of the global programme, coupled with the elimination of the disease from most of Europe and North America, led to a loss of interest in its eradication from the early 1970s until the late 1990s. Only three of the 1,223 new drugs developed during the period from 1975 to 1996 were antimalarials, according to Nature.

The past five years, however, had seen a pronounced reawakening of interest in malaria in richer countries of the world, the magazine added. The population at risk in Africa alone is around 500 million and increasing rapidly.

[For text of article "Link between climate and malaria broken" see www.nature.com]


This article was produced by IRIN News while it was part of the United Nations Office for the Coordination of Humanitarian Affairs. Please send queries on copyright or liability to the UN. For more information: https://shop.un.org/rights-permissions

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