Mosquitoes Become Immune to Deet


Ryan O'Hanlon

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Is there a more ominous insect-related quote than this one? “Mosquitoes are very good at evolving very, very quickly.” If so, I don’t want to hear it.

According to a recent study from a group of scientists at the London School of Hygiene and Tropical Medicine—including Dr. James Logan, author of the above quote—the repellent Deet affects mosquitoes on first exposure, but it loses its power soon after. In other words, they seem to become immune to bug spray.

To find out more, researchers from the London School of Hygiene and Tropical Medicine took some A. aegypti mosquitoes in the laboratory and tempted them with a human arm covered in Deet.

As expected, the repellent put the insects off their potential meal.

However, a few hours later when the same mosquitoes were offered a chance to dine again, the researchers found that the Deet was less effective.

The researchers stressed that their findings don’t mean that people in high-risk areas should stop using Deet. They hope their research will help with the development of more effective types of mosquito repellent.

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