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Water resources development and malaria transmission in Sub Saharan Africa: What is needed?

April 15, 2011 - 09:03 -- Solomon Kibret

In recent years, there seems to have a boost in construction of large dams and irrigation schemes in sub-saharan Africa, mainly in Ethiopia. With recognition of such infrastructures to ensure economic development and allevate poverty, Ethiopia is building large dams and constructing large irrigation schemes in parts of the countries where malaria is endemic. However, such water infrastructures have been shown to intensify malaria transsmission in communities living close to water storages. Hence, we need to devise tools to mitigate malaria transmission and breeding of mosquito vectors around water impoundments.

For large dams, reservoir management have been widely accepted to creat condition unsuitable to malaria mosquito breeding. Faster drawdawn of reservoir water levels has been associated with lower larval mosquito abundance at the shoreline of the reservoir.

For irrigation schemes, canal water management options could potential mitigate malaria transmission by affecting larval mosquito develompent in irrigated fields.

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William Jobin's picture
Submitted by William Jobin on

You are right Dr. Solomon

New hydroelectric dams are being planned and built all over Africa because of the unmet needs for electricity. And new irrigation systems are being built because of the rising demand for food. It is not just in Ethiopia, but all over Africa. Unfortunately WHO is not aware of this and are doing nothing about preventing the consequent expansion of malaria transmission.

In your work in the Ziway area you pointed out that anopheline breeding occurs in canal leakage and in irrigated fields. We found similar problems in Sudan, but breeding in the fields usually occurs with rice cultivation because the flooding is usually maintained for months. When other crops are grown without such high water maintenance requirements, the anophelines breed in the leakage, in spills and in drains (Gaddal 1986 The Blue Nile Health Project, J Trop Med Hyg v68(2)). So crop selection has an impact on malaria transmission. Have you noticed that in Ethiopia?

You point out that water level fluctuations have been used to control anophelines in reservoirs. But shoreline straightening, improved drainage, and land levelling round the villages near reservoirs can also be used (Bomblieset al 2009 A mechanistic approach..Malaria J v8:223) Further information can be found in the WHO Offset publication 66 Manual on environmental management for mosquito control,1982.

We summarized the options for reducing malaria in dams and irrigation systems in our 1999 book Dams and Disease published by Francis, and I continue to publish less expensive monographs through Boston Harbor Publishers.

I hope you will continue to work on water resources and malaria, and will find a way to advise your power and irrigation authorities in Ethiopia on the ways to reduce the problem by proper design and operation. Since WHO is ignoring the problem, maybe the engineers will help you with it.

Bill

William Jobin Director of Blue Nile Associates

Submitted by Guest (not verified) on

Thank you so much Dr William for your note. I really appreciate that. Yes, it seems that WHO has ignored the issue despite recent boost in building of large scale dams in Africa. The bad news is most of these dams are being built in Africa where availability of stored water intensifies malaria transmission. I am not anti-dam, rather I strongly believe that dams will bring economical values especially in Africa where food security is a challenge. But my view is the fact that large reservoirs could enhance malaria transmission is largely ignored. Thus, whenever we plan water resource schemes we need to plan on measure to mitigate adverse health impacts. This shall not be overlooked. I wish while designing, implementing and operating water resource schemes, those people who make decision on the operation of these schemes always keep malaria/ health issues in the back of their mind.

My best regards,

Solomon