الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Schistosomiasis is now generally considered to be one of the most
important and rapidly spreading parasitic diseases posing a real threat to largescale
irrigated agriculture and hydroelectric power development schemes in
many tropical and sub-tropical parts of Africa, the Middle East, the Far East,
the Caribbean Islands and many parts of South America. An estimated 200-
300 million people are currently affected by this debilitating disease, while
another 400-500 million are potentially exposed to it (Lemma, 1983).
Schistosomiasis is a tragic example of a man-made disease. Well
intended agricultural and other water-utilizing projects in developing count-ries
have often led to the creation of new breeding habitats, people brought to work
together in such areas often must drink from, bath and labour in the same
canals, all too often, human wastes are also excreted or otherwise damped or
washed in the same water. This deadly combination is all that is needed for a
rapid spread of this disease, especially among children who are highly
vulnerable.
In Egypt, the disease is endemic and considered to be a major public
health problem. It is transmitted to man via the snails, Biomphalar/a
alexandrina and Bulin us truncatus, the intermediate hosts of Schistosoma
manson/ and S. /Jaematobium, respectively.
The crucial role that molluscicides can play in the effective control of
Schistosomiasis and other snail-borne diseases of humans and livestock has
been well established over the decades since the discovery of the life cycles of
these parasites.
Numerous Schistosomiasis-control projects in Egypt, the Sudan, the Middle East, Japan, the Philippines, China, Brazil and other countries,
have shown that snail control by rnolluscicides, either alone or in combination
with other methods (chemotherapy, environmental measures, health edu~ation,
... etc.) can be a rapid and effective means of reducing or eliminating
transmission (Lemma, 1983).
The use of chemical mollusclcides for the control of snail hosts of
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Bilharziasis has been widely accepted as one of the most promising end
practical means of controlling the disease.
Baylusclde (Nlclosamlde), Bayer 73 Is a candidate mollusclclde. It Is
the ethanolamine salt of 5,2-dl- chloro-4-nltrosallcylanlllde. It Is available as 70
% wettable powder and 25 % emulsifiable concentrate. In practical use, a
concentration of 0.6-1 mg/L is recommended with an exposure time of 8 h
(WHO, 1973) or 0.33 mg/L for 24 h (Branlah and Prentice, 1981).
Accordingly, there is a great possibility for contamination of application
sites by this compound.