They act as mechanical careers of disease causing agents. They spread the micro organisms that cause diseases like typhoid, cholera, dysentery and poliomyelitis.
Life cycle and habits
Houseflies undergo complete metamorphosis. The female housefly lays its eggs in any decaying organic matter such as garbage, rotting fruit and human excreta. The eggs hatch in larvae within 24 hours. Larvae feed in decaying material and moult about three times. After about 3 to 6 days, the larvae enter the pupal stage. The pupal stage lasts about 5 days. The adult fly that emerges from the pupal usually has a life span of about 2 to 3 weeks in the tropics. Houseflies move around mostly during the day and like warm places. At night, they rest usually in twigs, fences, wires and ropes. They have roving habits, going almost everywhere and feeding on almost anything from human excreta to human food. They ate thus very effective in collecting and spreading pathogenic micro organisms.
Control of Houseflies
Environmental control is aimed at destroying the breeding places of Houseflies by improving sanitation. This is usually done by
• burning or burying all garbage;
• storing household refuse in covered bins for collection and disposal by public health services;
• keeping compost and manure stored in pits dry and turning them often to get rid of heat (which favours breeding of maggots) ; and
Improving sewage disposal facilities
Chemical measures use insecticides to kill maggots and the adult flies. Insecticides may be used in Baird, cords and strips which attract flies onto them. Fly baits consists kg a mixture kg an insecticide and a sugary material. These baits are placed in areas where large numbers of flies occur. Cords and strips are impregnated with insecticide and hung from the ceiling of the house or shed.
Other measures include : fitting the doors and windows of houses with wire netting and applying physical attack to kill houseflies directly.
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