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molluscicides for many decades in Egypt, the Sudan, and other parts of the
world to control schistosomiasis.
Recently, however, the ethanolamine salt of niclosamide (bayluscid), has been
found to be more effective and is currently the only molluscicide recommended
by the World Health Organization (WHO) for global use. However,
partly because of its high cost (26 000 USD/t in 1974), most developing
countries, especially those in Africa, are not using it to control schistosomiasis.
Meanwhile, many well-intentioned agricultural development and water conservation
schemes are providing more sites for snails to breed, and schistosomiasis
is spreading rapidly.
Endod: a potential pesticide
Endod, a natural molluscicide, is biodegradable. Its active principle decomposes
rapidly, breaking down to inert and nonharmful material within a few
days. Accordingly, a concerted effort to develop simple methods for the
development and safe use of endod could pave the way for use of other plant
pesticides in developing countries, Ideally, each country where schistosomiasis
is endemic should select local molluscicide-producing species for snail
control. In all cases, however, the principle and approach remains the same.
The use of endod berries as a soap, dating back hundreds of years, led to
studies of its detergent, antifungal, antiprotozoan, spermicidal, and molluscicidal
properties (Lemma et al. 1979). The berries have been traditionally used
in Ethiopia and other African countries for washing clothes and as a medicine
(Hutchinson and Dalziel 1929; Dalziel 1936; Watt and Breyer Bandwik 1962;
Humbert 1971; Thiseltch-Dryer 1973; Legesse and Kloos 1990). However, the
molluscicidal property of endod has given it international recognition as a
potential means of control for snails that transmit schistosomiasis (Lemma et
al. 1979).
Endod or soapberry plant (Phytolacca dodecandra) is a member of the Phytolaccaceae
and is a dioecious scandent shrub or liana averaging 2-3 m in
height, but as climber sometimes growing as tall as 10 m. The male flowers
are light yellowish green, in long staminate racemes, and bear no fruit. The
female flowers are light yellowish green in short staminate racemes, producing
fruit that is five lobed and 1 cm in diameter; ripe fruits are pink or red
(Hutchinson and Dalziel 1929). Under favourable climatic conditions in Ethiopia,
the plant bears fruit from November to June (Legesse 1983).
The molluscicidal property of endod has been studied over the last 25 years
at the Institute of Pathobiology at Addis Ababa University, the Tropical
Products Institute in London, the Stanford Research Institute in California, the
G.W. Hooper Foundation at the University of California, the Harvard School
of Public Health in Boston, the Public Health Service Laboratory and Field
Station in Puerto Rico, the US Naval Medical Research Unit in Cairo, Carleton
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