In malarial eradication programme, the basis of using insecticide is to reduce lifespan of mosquito by less than

VECTOR CONTROL STRATEGIES Vector control is still one of the primary weapons to control malaria in endemic areas. (a) Anti-adult measures (i) Residual spraying : The discovery of DDT in 1940s and followed by other insecticides revolutionized malaria control. The spraying of the indoor surfaces of houses with residual insecticides (e.g., DDT, malathion, fenitrothion) is still the most effective measure to kill the adult mosquito. It has been observed that discontinuation of spraying has very often led to the resurgence of malaria. This implies that spraying once applied may need to be continued for an indefinite period. If indoor spraying is to have any effect, then exhaustive coverage is needed. Indoor house spraying Reduces the longevity of the vector. Malathion and fenitrothion are organophosphate insecticides which are being used with increasing frequency For malaria control following the development of vector resistance to DDT (ii) Space application : This is a major anti-epidemic measure in mosquito-borne diseases. It involves the application of pesticides in the form of fog or mist using special equipment. The ultra-low-volume method of pesticide dispersion by air or by ground equipment has proved to be effective and economical. Outdoor space sprays reduce vector population quickly. {iii) Individual protection : Man-vector contact can be reduced by other preventive measures such as the use of repellents, protective clothing, bed-nets* (preferably impregnated with safe, long-acting repellent insecticides), mosquito coils, screening of houses etc. The methods of personal protection are of great value when properly employed. However, they have rarely been used on a large scale because of cost Ref : Park 25th edition Pgno : 318