Malathion is an organophosphate insecticide which acts as an acetylcholinesterase inhibitor. In the USSR, it was known as carbophos, in New Zealand and Australia as maldison and in South Africa as mercaptothion. Pesticide use Malathion is a pesticide that is widely used in agriculture, residential landscaping, public recreation areas, and in public health pest control programs such as mosquito eradication. In the US, it is the most commonly used organophosphate insecticide. A malathion mixture with corn syrup was used in the 1980s in Australia and California to combat the Mediterranean fruit fly. In Canada and the US starting in the early 2000s, malathion was sprayed in many cities to combat west Nile virus. Malathion was used over the last couple of decades on a regular basis during summer months to kill mosquitoes, but homeowners were allowed an exemption for their properties if they chose.. Mechanism of action Malathion is an acetylcholinesterase inhibitor, a diverse family of chemicals. Upon uptake into the target organism, it binds irreversibly to the serine residue in the active catalytic site of the cholinesterase enzyme. The resultant phosphoester group is strongly bound to the cholinesterase, and irreversibly deactivates the enzyme which leads to rapid build-up of acetylcholine at the synapse. Production method Malathion is produced by the addition of dimethyl dithiophosphoric acid to diethyl maleate or diethyl fumarate. The compound is chiral but is used as a racemate. Medical use Malathion in low doses (0.5% preparations) is used as a treatment for: Head lice and body lice. Malathion is approved by the US Food and Drug Administration for treatment of pediculosis. It is claimed to effectively kill both the eggs and the adult lice, but in fact has been shown in UK studies to be only 36% effective on head lice, and less so on their eggs. This low efficiency was noted when malathion was applied to lice found on schoolchildren in the Bristol area in the UK, and it is assumed to be caused by the lice having developed resistance against malathion. Scabies Preparations include Derbac-M, Prioderm, Quellada-M and Ovide. Safety General Malathion is of low toxicity. In arthropods it is metabolized into malaoxon which is 61x more toxic, being a more potent inhibitor of acetylcholinesterase.According to the United States Environmental Protection Agency, no reliable information is available on adverse health effects of chronic exposure. In 1981, Malathion was sprayed over a area to control