(NEW YORK) -- Mosquitoes may be developing a tolerance to DEET, according to new research at the London School of Hygiene and Tropical Medicine.

Researchers at the school have found that mosquitoes are repelled when they are first exposed to the bug spray, created in 1946 by the U.S. military. But according to researcher Nina Stanczyk, mosquitoes get used to the smell and begin to ignore it, just like humans.

Researchers say, however, not to give up on DEET, as it is still the best defense against the disease-carrying insects.

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