This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and Health, Subject name: Social & Preventive Medicine
[{'content': 'Household insectiside used for malaria- \nSelect and explain. \nA. Malathion, B. Pyrethrum, C. Paris green, D. Permethrin', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Malathion* Insectisides used for control of malaria are-i) Residual sprapy-# In residual spray, spraying of houses with residual insectisides is done. Residual insectisides remains active over extended periods i.e., they have residual action even after the time of spray.# Commonly used residual insectisides are - Malathion, DDT, Lindane, propoxure (OMS-33).ToxicantDosage in g/m2Average duration of effectiveness (months)DDT1 to 26 to 12Lindane0-53Malathion23OMS-3323ii) Space spray# Space sprays are those where the insecticidal formation is sprayed into the atmosphere in the form of a mist or fog to kill insect. Action is short lived and temporary since there is no residual action.# The most commonly used space spray insecticide is Pyrethrum.# New equipment has been developed to use residual insectiside as space spray by ultra low volume (ULV) technique. Malathions and fenthion are most commonly used.", 'role': 'assistant'}]