Which is why I'm currently reading The Excellent Powder: DDT's Political and Scientific History. The third chapter entirely pertains to widespread misunderstanding among policy makers of how DDT works. To quote the chapter summary:
Despite high-quality and widely published scientific evidence and abundant experience from the field showing that DDT primarily acts as mosquito repellent, public-health officials in WHO as well as many malaria scientists have clung to the notion that DDT acts primarily as a toxic agent. So what? If the insecticide works, who cares how it actually functions? Yet, understanding how DDT works is, in fact, crucially important because many DDT detractors see a limited usefulness for the insecticide because of the prospect of toxic resistance. They argue that if mosquitoes develop resistance to DDT and it no longer kills them, the chemical has no use for reducing malaria. They would be right if DDT were primarily a toxic agent, but in fact it is primarily a repellant that acts secondarily as an irritant and lastly as a toxic agent. This means it is still useful in malaria control even in the presence of resistance to toxicity. Thus, a lack of understanding of how DDT works has resulted in it not being used and lives being lost.What's interesting is how neatly this encapsulates many of the themes that I write about here on the blog. First is an intuitive idea about how DDT works, which is only slightly wrong or is mostly true. Yet when used to inform or base a larger policy decision the small errors compound and lead to catastrophe.
I'll be trying more posts like this (short, observational, reportorial) for the next while. Feel free to let me know what you think of them, or if you hate them in the comments or on twitter.