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When will permanent methods be added by PMI?

March 11, 2016 - 14:43 -- William Jobin

In a recent analysis of the US Presidential Malaria Initiative (PMI) by Richard Oxborough, it was pointed out that indoor spraying is being reduced and even abandoned as a control measure because of resistance to the cheaper insecticides. In Angola, they have completely abandoned indoor spraying as a method. The newer insecticides are too expensive.

It is alarming that now the only effective control method available is drugs. What will happen when drug resistance spreads? Is PMI prepared for this?

The decrease and even abandonment of indoor spraying by the otherwise carefully managed attack on malaria by PMI in Africa is no surprise, in fact we predicted it when we helped start PMI in Angola in 2005. But why have our recommended solutions been ignored by the management of PMI? It was clear even in the beginning that the money wasted on temporary pesticides and temporary bednets could better have been used in permanent elimination of breeding sites, as well permanent improvements in housing such as improved eaves and metallic screens.

Bednets last 2-3 years, but metallic screens last 10-20 years. Sprayed insecticides last a few months, but drainage and filling of breeding sites lasts decades. The economic advantages of permanent measures are clear, especially when the temporary measures have been used now for 11 years and many millions are wasted every year on these temporary fixes. The seductive appeal of the quick-fixes of spraying and bednets during the early years of PMI should no longer be tolerated because they are neither durable nor economic. As Oxborough describes the current PMI strategy, it is "fragile" and could easily be washed away like the insecticides.

For 11 years pesticides and bednets have been purchased with billions of US dollars, with no permanent changes being made in the ecology or epidemiology of transmission. Thus the decreases in malaria transmission are temporary and precarious. And about a billion US dollars have been used for these temporary measures. Was that wise?

Admiral Ziemer and friends in Washington should start making permanent changes in the transmission scene. Ziemer recently expressed admiration for the anti-malarial work described by Margaret Humphrey in her recent book on malaria contol in the USA before 1951. This was accomplished before the widespread use of DDT and chloroquine, by permanent environmental improvements. Such an approach is not only more durable, but also more economic.

If the same billions had been invested in permanent changes in Africa such as drainage and housing improvements, the progress made in the last 11 years would not be at risk.

Isn't it obvious by now?

Bill Jobin of Blue Nile Associates


Submitted by Richard Oxborough on

Thank you for your commentary Bill.
Respectfully, I disagree with your conclusion that use of IRS and LLIN should be abandoned in favor of house improvement and larval modification. While there is clear evidence showing that house improvement by closing mosquito entry points such as eave, door, window and roof spaces can protect against malaria transmission, there are major questions to be answered.
What form would this house modification take? How would it be scaled up and sustained? Is it cost-effective?
There are just as many unanswered questions about the effectiveness of larval modifications. Larval modification was so successful in places such as Italy because the local malaria vectors, An. sacharovi and An. labranchiae, were limited to permanent swamps that could be drained. In rural Africa An. gambiae breeding sites are often numerous and ephemeral. Lindsey and others showed in The Gambia in an area of numerous and extensive breeding sites larviciding produced no reduction in transmission.
To abandon LLIN & IRS- the only proven vector control interventions brought to scale in Africa- would be folly at this time. PMI funded control programs based on IRS and LLINs have had an enormous impact in terms of reducing child mortality and malaria incidence. There are certainly questions remaining about sustainability in the face of increasing mosquito resistance and higher insecticide prices, but this is being addressed through organizations such as the IVCC. There are positive signs of an insecticide pipeline being developing with new neonicotinoid IRS formulations and chlorfenapyr on the way. New LLINs with different modes of action are also in the late development stages and should be on the market soon. Certainly more funding should be made available to examine the role of house modification and larval control, but not at the detriment to proven interventions.

William Jobin's picture
Submitted by William Jobin on

I am hoping other people will add to this discussion, but would first of all like to point out that there are some exciting new approaches to fixing eaves. And if you note the title of my comment, I advocate 'adding' the permanent methods to the current temporary methods, not to replace them....

Secondly, what is the point of looking for new pesticides? You have pointed out that the newer ones currently being promoted are too expensive to use. Additional new pesticides will be even more expensive.

William Jobin Director of Blue Nile Associates