Central nervous system insects, protection

By warding off biting insects, DEET protects against the diseases they carry. Mosquitoes, for example, carry diseases such as malaria, one of the most serious diseases in the world, responsible for an estimated three millions deaths a year encephalitis, an infection that causes inflammation and swelling of the brain and West Nile virus, an organism that affects the central nervous system and poses a serious threat to both humans and other animals. Ticks carry Lyme disease, an infection spread hy the deer tick that causes a skin rash, joint pain, and flu-like symptoms that can develop into a debilitating and permanent health problem if not treated early. 

The chemical mediators in the central nervous system of insects are far from completely explored, but acetylcholine (ACh) and octopamine (2.35) play important roles. The neurotransmitter at insect ganglia is acetylcholine, but that at the neuromuscular junction is not acetylcholine but L-glutamic acid (Usherwood and Machili, 1968), and for this neurotransmitter, no selective antagonist has yet been found. The receptors for the neurotransmitters are well protected by selectively permeable membranes. 

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