Tropical Health Matters

Recently Matt Lynch of the Johns Hopkins Center for Communications Programs and the USAID NetWorks Project was asked about the challenges of disposing old ITNs. His response has been shared on Malaria Update, but we thought readers on Malaria Matters, who are not Update subscribers, could also learn from Matt’s Ideas. Matt urges that each country and community needs to find its own economic and ecological solutions as seen below.

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I would urge a careful look at all the options (including leaving the nets in the households) before leaping into actions which may end up with worse consequences than no action at all.

Much that I have heard on this topic begins with the assumption that nets must be collected – this is not necessarily true, and no one has been able to adequately describe to me exactly what the problem of leaving the used nets for households to re-purpose might be.  They are, on the other hand, very ready to describe the massive costs associated with collecting the nets, and the problems which will follow from concentrating enough old nets in one spot to actually have insecticide and plastic concentrations which do become quantifiable problems.

As far as I can tell from asking the manufacturers, most pyrethroids decay when exposed to UV light, and are broken down by soil bacteria.  This is why pyrethroids are so popular in agriculture – they don’t persist in the environment.  They are apparently quite toxic to fish, so that’s worth exploring in the island environments.  Dumping them into the sea is probably not a great idea.

In Africa, one frequently sees old, holed nets being used to cover plants, chicken coops, or to screen windows.  Such uses, as far as I can tell, do no harm and probably some good (who knows, the residual insecticide may help control chicken mites?).  In addition, they provide an opportunity for the UV light and soil bacteria to begin breaking down the insecticides.

One might expect polyethylene nets to pose more of a problem in terms of solid waste, but I have not seen any reports of drains being blocked by old bednets (plastic bags, frequently!).  Polyester nets are even more difficult to imagine as a serious solid waste problem – after all, there were millions of pretty toxic-looking polyester leisure suits sold in Africa through the 1980’s and no one seems concerned about their disposal…

So, I don’t mean to trivialize the issue;  I think we need a clear description of precisely what the problem is with letting households dispose of their worn-out nets through their usual practices.  There may well be harmful disposal practices that need to be addressed, but I do think we need a clear description of the problem before we rush into complicated, expensive and potentially hazardous “solutions”.   I personally doubt the optimal solution will be to collect the nets.

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