Yellow fever mosquito's resistance to DEET !.....

In continuation of  my update on mosquito repellents,  I found this info  interesting to share with. We know that N,N-Diethyl-meta-toluamide, DEET (see structure), is the most common active ingredient in insect repellents. It is intended to be applied to the skin or to clothing, and is primarily used to repel mosquitoes. In particular, DEET protects against tick bites, preventing several rickettsioses, tick-borne meningoencephalitis and other tick-borne diseases such as Lyme disease. It also protects against mosquito bites which can transmit dengue fever, West Nile virus, eastern equine encephalitis, and malaria. 

Now researchers from Swedish University of Agricultural Sciences (SLU) and associates in the UK, for the first time in laboratory tests have shown that yellow fever mosquito has developed a resistance to the mosquito repellent DEET.

"Through testing, we have found that yellow fever mosquitoes no long sense the smell of DEET and are thereby not repelled by it. This is because a certain type of sensory cell on the mosquito's antenna is no longer active" says Rickard Ignell, a researcher at the Division for Chemical Ecology at SLU in Alnarp....

Rickard Ignell performed the research in collaboration with Rothamstead Research in the UK. The scientists have thus seen that the sensory cell on the mosquito's antenna has stopped reacting to DEET. This have many explanations, such as the protein that binds in to DEET having mutated. The researchers are now urging restrictiveness in the use of DEET and other mosquito repellents on a large scale in a limited area, in order not to make other mosquito species resistant. The mechanism is still to be established, but in my opinion its a interesting finding....

Ref : http://www.pnas.org/content/early/2010/04/26/1001313107