Anopheles gambiae mosquito. Credit: James D. Gathany/CDC/The Public Health Image Library
Key points:
- The current insecticide used to control malaria in high-risk areas is up to 14% effective.
- Microwaving the insecticide increases its effectiveness 12 times over.
- Scientists say more research on the crystalline structure of insecticides will produce better vector control products.
In high-risk areas like West Africa, health officials use the insecticide deltamethrin to control malaria. However, the insecticide is only marginally effective—between 4 and 14%—and Anopheles gambiae in the area are becoming resistant to it.
New York University researchers recently created a new and improved crystal form of deltamethrin by simply heating the existing form in a microwave for five minutes. The researchers say the new form is up to 12 times more effective against mosquitoes than the original insecticide.
For the study, published in Malaria Journal, the researchers tested five different strains of insecticide-resistant Anopheles mosquitoes. They found that the new deltamethrin was 100% effective against the mosquitoes within 10 to 20 minutes of contact. In contrast, the original form of deltamethrin was only 4% effective against three strains of mosquitoes within 24 hours and 14% effective against a fourth. Moreover, the more active deltamethrin has maintained its potency for at least 13 months—and counting.
“We buy some commercial product, stick it in a microwave for the time it takes to make popcorn, and it is supercharged. It is remarkably simple intervention, with dramatic consequences," said Bart Kahr, professor of chemistry at NYU and one of the authors of the article.
Kahr and team say understanding how the crystalline structure of insecticides could affect bioactivity is critical for the development of the best possible vector control products.
“Greater knowledge of the crystallization behavior of insecticides and the application of knowledge from crystal engineering could help to overcome resistance. It could also reduce the cost of vector control products, allowing smaller quantities of compound to be used in its most efficacious physical state to greater effect,” the authors conclude.