ACARICIDES

ACARICIDES are chemicals used to kill ticks and mites. Ticks belong to an order of the arthropods called Acarina, which also contains the mites; and chemicals used against the latter may be referred to as SCABICIDAL agents (or miticides in USA). Some ticks transmit other diseases (including Lyme disease, typhus and Rocky Mountain spotted fever), but they may themselves cause local irritation (e.g. in scabies caused by itch-mites Sarcoptes scabiei), and sometimes serious skin lesions and more general toxic manifestations, scabicidal drugs are used to kill the mites that cause scabies, in which the female mite tunnels into the top surface of the skin in order to lay eggs, causing severe irritation as she does so. Newly hatched mites, which also cause irritation with their secretions, then pass easily from person to person by direct contact; so every member of an infected household should be treated, and clothing and bedding should also be disinfected. Treatment is usually with local applications of a cream to kill the mites, but some agents can be irritant or have toxic manifestations; further resistance to many of these agents has developed in many ticks and mites. Acaricides that can, or have been used, include the halogenated hydrocarbons (e.g. dieldrin and lindane), organophosphorus compounds (e.g. malathion), carbamates (e.g. carbaryl), pyrethroids (e.g. permethrin, phenothrin), and a number of other substances, including benzyl benzoate, crotamiton and monosulfiram. Some of these agents are also used as pediculicidal treatments against lice.