Monday, August 10, 2009

Insect repellent DEET is a potential neurotoxin


Unfortunate but somehow unsurprising recent research finds that DEET, the compound widely used as an insect repellent, is potentially neurotoxic, based on its ability to inhibit the crucially important enzyme acetylcholinesterase. The enzyme, known to biochemists as a classic example of catalysis, is centrally involved in the nervous system and the target of several particularly nasty compounds, notably Sarin.

Scared? Well calm down. It will be ok. I promise.

I don’t subscribe to the “all chemicals are evil” attitude quite popular in some circles, notably organic food and anti-pharmaceutical crowds. That said, I’m not a fan of blind faith in chemicals either. There’s a cost-benefit balance with any compound. One shouldn’t dismiss the utility of a compound because it has some negative effects; there can be safe applications of a compound if used correctly. Conversely, one shouldn’t assume that there are no negative effects of chemical products and use them indiscriminately. Use should be in moderation, and only when genuinely needed. Acetaminophen (Tylenol™) illustrates this point well. The compound is quite benign and functions as an effective painkiller in normal doses, but high doses can cause severe liver toxicity.

DEET, long sprayed in high doses frequently, may need to have its use curbed, pending further research on the actual effect (if any) that it might have on mammals and humans specifically.

However, we need to make sure we don’t forget that there are important benefits as well.

DEET-containing insect repellents are not merely used to avoid a nuisance. In the case of diseases like malaria, Dengue Fever, and West Nile virus, the repellence of insects can markedly reduce the risk of disease. The continued use of DEET will depend on the renewed evaluation of the safety of the compound, balanced with its efficacy as a repellent.

Now, I’m going to go duck as the irrational public storm about the safety of insect repellents picks up speed. We all know it’s going to get ugly.

Where I first caught this: Report: Deet, popular and potent insect repellent, is neurotoxic
On ScienceDaily: Popular Insect Repellent Deet is Neurotoxic
And the article on BMC Biology: Evidence for inhibition of cholinesterases in insect and mammalian nervous systems by the insect repellent deet

No comments: