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How to slow the Resistance Treadmill

February 25, 2015 - 15:27 -- William Jobin


Repeated application of insecticides and drugs to fight malaria on a large scale has historically caused the development of resistance. Thus during the Global Malaria Eradication Program of the 1960’s, Sudan, Turkey, Pakistan programs of Indoor Residual Spraying cycled through as many as 8 insecticides before the programs collapsed. The drug chloroquine was used globally until resistance emerged in SE Asia, and then gradually spread westward to India and Africa. The Resistance Treadmill then caused the Eradication Progam to collapse in 1969. The Resistance Treadmill is a universal problem for public health programs which achieve widespread and intensive use of biocides and drugs.

The way to slow the Resistance Treadmill is to minimize the use of biocides and drugs by adding non-chemical control methods to the strategy. Thus the use of microbial larvicides and screening of houses, besides being very cost-effective, have the added advantage of reducing the need for such heavy application of biocides, and the repeated and global administration of precious drugs. Thus the alarming rise of resistance to drugs and biocides will at least be slowed.

Screening of houses might seem an expensive approach, but its cost should be compared with the cost of repeated spraying of insecticides. In 2009 USD this cost is about $6 per person per year. In a household of 6 people, after 10 years the amount spent on spraying is about $360 per house, enough for a good set of screens. Furthermore, the cost-effectiveness can be enhanced by starting with the houses in best condition, where it is easy and inexpensive to mount good screens on the windows.



Bart G.J. Knols's picture
Submitted by Bart G.J. Knols on

Nice views, and for anyone with a little background in evolutionary biology common sense. The problem with the current policy to deal with resistance is that resistance management is advocated but hard to implement let alone be defined in terms of what it should deliver. Resistance breaking is easier to grasp - it is a tool, method, or active that can kill resistant mosquitoes.

In the Kilombero Valley of Tanzania we have now completed 1559 houses: full window screening, door improvement, closing of the eaves, and installation of eave tubes (with actives). Results are as expected: the indoor density of anophelines is reduced by 85-90% for both gambiae sl and funestus.

Eave tubes are ideal in the sense that they offer management options since you can put more than 1 active on (the tubes are installed at eave height and therefore out of reach of house occupants).

Compared to the cost of IRS, eave tubes are highly competitive and use 98% less insecticide.

Coarse application of insecticides (spraying the whole house) may not be necessary if we use the behavioural ecology of the target insect cleverly (i.e. they prefer to enter the house through the eaves). Cheaper, equally effective, greener.

William Jobin's picture
Submitted by William Jobin on

Bart, that is really good to hear! Congratulations for trying to outwit the pesky buzzing critters.
Incidentally, although they don't give precise figures, if one studies the latest financial reports from the US PMI, it is quite likely that indoor spray costs have tripled recently and are now close to $18 per person protected per year.
These huge cost increases might be due partly to the switch to bendiocarb.
This gives even more reason to support your approach.

William Jobin Director of Blue Nile Associates