James Logan, Nina Stanczyk and colleagues from the London School of Hygiene and Tropical Medicine published research in the Feb. 20, 2013, issue of the open access journal PLOS ONE that is the first evidence that mosquitoes develop a resistance to the repellent effects of DEET in a short time frame.
The smell of DEET is what repels mosquitoes.
The researchers studied Aedes aegypti mosquitoes, which are notorious for biting during the day and are capable of transmitting dengue fever.
A brief exposure to DEET was sufficient to make some mosquitoes less sensitive to the repellent but not all mosquitoes.
Mosquitoes that did develop a lower sensitivity to DEET would approach and bite test subjects three hours after the initial exposure despite the presence of DEET on the human test subjects.
The resistance to the repellent quality of DEET was found to be correlated to a decrease in the sensitivity of odor receptors on the mosquito's antennae.
Previous studies have seen the genetic development of DEET resistance in some mosquitoes.
This is the first known proof that some mosquitoes can develop a temporary resistance to the repellent effects of DEET that is only physical in nature.
The researchers intend their present research to refine the existing methodology for insect repellent effectiveness protocols and produce better repellent effects.
Nina M. Stanczyk 1,2, John F. Y. Brookfield 2, Linda M. Field 1, James G. Logan 3 *
1 Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, United Kingdom, 2 Centre for Genetics and Genomics, School of Biology, University of Nottingham, Nottingham, United Kingdom, 3 Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom