الفهرس 
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Abstract
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For more than 90 years, the house-flies have been regarded as a potential
and important vector for transmission of several enteric infections such as
dysenteries, infantile diarrhoea, typhoid, food poisoning, cholera and parasitic
worms (helminthes). They have been also incriminated as vectors of poliomyelitis
and certain skin diseases such as yaws; hence the house flies constitute one of the
greatest problems of human public health. Also, mosquitoes create a health
menace for human, animals and birds. Some of the most deadly diseases of man,
such as malaria, encephalitides, yellow fever, dengue fever and filariasis are
mosquito borne. Recently, it had been reported that mosquitoes can transmit
hepatitis B virus (El-Alarny et al .,1979) and AIDS (Siemens, 1987). Therefore,
the control of these vectors, by chemical insecticides had been used as a method
to combat these diseases in various parts of the world.
Today, the commonly used insecticides are neurotoxicants and act by
poisoning the nervous systems of the target organisms (Busvine, 1980). The
central nervous system (eNS) of insects is highly developed and not unlike that
of the mammals. Although the peripheral nervous system (PNS) of insects is not
as complex as that of the mammals, yet there are striking similarities (Amdur et
al., 1991). As a fact, insecticides are not selective and affect nontarget species as
readily as target organisms, therefore it is not surprising that a chemical that acts
on the insect nervous system will elicit similar effects in higher forms of life
(Gruzdyev et al., 1983).