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The problem with WHO and their approach to Larval Source Management

August 14, 2013 - 16:05 -- William Jobin

I just had a chance to review the new LSM manual of WHO, thanks to Mike Reddy of Yale,

Now I think I am beginning to understand why WHO and PMI respond so poorly to our proposals for integrated and durable attacks on malaria. Their Larval Source Management Manual shows why they don't hear what we are saying. Although they describe LSM as a 4 point attack; (1) reduction of breeding grounds,(2) manipulation of water in breeding sites, (3) larviciding and (4) biological control, IN FACT the manual deals almost exclusively with spray applications of chemical and biological larvicides.

They say that larviciding should only be used as a supplemental measure, for "Fixed, Few and Findable" situations. For the rest of the manual - 90% - they go on to delineate all the problems with larviciding. Although they talk about Integrated Vector Management, they have put up a straw horse of larvicide spraying, and spend all their energy shooting the straw horse.

When my friend in Washington tried to get at PMI through the Congressional appropriations committee, asking why PMI didn't use community based attacks on draining and filling habitats near homes and within villages, the response was the larviciding argument! So we are dealing with folks who have their heads in the sand.

In general, the LSM manual was too narrowly focussed on larviciding, and thus a waste of paper because it ignored the classical success of engineering measures which permanently eliminated larval breeding areas. To give some examples - the Pontine Marshes in Italy, coastal swamps in the Panama Canal Zone and Puerto Rico, and the entire TVA program before DDT and chloroquine, suppression of malaria in Malaysia and Indonesia with water manipulation. Obviously none of the writers are familiar with the engineering literature on malaria control, especially that from the pre-War period of the 1930's.

In the manual they repeated engineering and drainage diagrams from the two older WHO manuals but with more colorful grafics, plus they reported a few case studies from Africa where larviciding was highly organized but fairly ineffective. But they did not report the case studies where it was highly effective, such as the Rockefeller campaign in Brazil.

There was some interesting detail on physical attacks on larvae by drainage and reduction of water spillage from irrigation and drinking water systems in Khartoum, but they were buried in Annexes which stressed how many people were wandering around spraying puddles. It was really a half-assed evaluation of Larval Source Management, and probably the best that the skeleton staff in Geneva could do. They have lots of money for graphic design, color fotos and publications, but not much for in-depth review and critical thinking.

I am more and more inclined to let WHO and PMI sink into their own swamp. Instead I am going to support people like Prof el Fatih of MIT who is developing real methods for mosquito control in African water resource systems. When the dust settles, and PMI goes the way of the 1960 GMEP, maybe the careful water management techniques that el Fatih has developed will at least reduce malaria around large irrigation and hydroelectric systems in Africa.

More and more, I see the value of carefully designed and operated hydropower systems for not only advancing the economies of African countries, but also for supplying an Exit Strategy for malaria control. When you can close up your house tightly at night, and use small electric fans to keep cool inside during the hot and humid malaria season, then the mosquitoes are left in the dark.



Submitted by Fran (not verified) on

The skeleton staff in Geneva can't do better because larvicide = money for pharmaceutical companies.
But how about Creating bt-treated breeding grounds to specifically Attract mosquitoes. Let them lay all their eggs where they can be killed.
A better economy helps reduce malaria also because it improves people's health and resistance.