Abstract

The effect of sublethal concentrations of Euphorbia milii latex on the infectivity of the larval stages ofSchistosoma mansoni to Biomphalaria alexandrina and to albino mice as well on these larval stages ofS. mansoni (miracidia and cercariae) were studied. The results showed that B. alexandrina infection with S. mansoni miracidia was greatly reduced by exposure to LC₀, LC₁₀, and LC₂₅ of the latex and also the infectivity of the S. mansoni cercariae shed from infected B. alexandrina post exposure to these concentrations to albino mice was suppressed. Exposure to LC₀, LC₁₀ and LC₂₅ of latex of E. milii caused a reduction in number of the produced cercariae per snail during the patent period and in the period of cercarial shedding. The mortality rates of miracidia and cercariae were elevated gradually by increasing the exposure period to latex of E. milii. The present results showed that the mean number of worms per mouse in the experimental groups was less than that of control as well. The total number of ova per g tissue; it can be concluded that the application of sublethal concentrations of latex of E. miliimay be helpful in control of schistosomasis.

Key words: Biomphalaria alexandrina, Schistosoma mansoni miracidia, latex of Euphorbia milii plant.