trial to assess the susceptibility of Biomphalaria Alexandrina to Schistosoma mansoni by protein electrophoresis, hepatic enzymes activities and random amplification polymorphic DNA [RAPD]

The identification of susceptible from refractory Biomphalaria alexandrina snails to Schistosoma mansoni is important in transmission studies and control programs. In this study, a trial was made in this respect utilizing three techniques, namely protein electrophoresis, assay for hepatic enzymes activities and Random Amplification Polymorphic DNA [RAPD]. The results show that, in protein electrophoresis there is one shard band only between susceptible and refractory snails [68.41KD]. The activities of hepatic enzymes, aspartate aminotransferase [AST] and alanine aminotransferase [ALT], alkaline [ALKP] and acid phosphatase [AcP], were higher in the tissue homogenate and hemolymph of susceptible snails than refractory ones. In RAPD, utilizing OPA-9 primer, approximately 1,900 bp band was characteristic for susceptible snails but did not appear in refractory ones

Agave angustifolia: a potential source of control agents against Schistosomiasis mansoni

A gave angustifolia [Agavaceae] has been studied for its potential effectiveness against Schistosoma mansoni and its intermediate snail host in Egypt Biomphalaria alexandrina. Thus, the methanolic extract of its leaves and the isolated saponins containing fraction were tested in vitro against the adult worms and the free living larval stages of the parasite. Both solutions were examined also on the survivorship of mature snails, egg production and hatchability. The results showed that the methanol extract of the leaves of Agave angustifolia had moderate molluscicidal effectiveness on B. alexandrina snails with LC50 =26.4 ppm after 24 hours at 25 +/- 1[0]C. While, the saponins containing fraction separated from the above extract showed much higher molluscicidal activity at the same conditions [LC50=5.9ppm]. Continuous exposure for 5 weeks to half the molluscicidal concentration [3ppm], showed a considerable effect on the survivorship of snails, and a decrease of egg production rate, being 16.9 eggs/snail vs 29 eggs/snail in control group. The egg masses of treated snails contain 20% less number of eggs/ egg mass than those of the control group and the total number of produced eggs is 52% less as a result of this exposure. Three different concentrations of the saponins fraction [the molluscicidal 0.1 LC50, 0.5 LLC50 and LC50] were tested on hatchability of B. alexandrina eggs and showed a sound reduction in hatchability being 56%, 77% and 82% respectively, compared to the control one [92%]. Saponins fraction of A. angustifolia leaves gave also marked miracidicidal and cercaricidal activities especially at the molluscicidal LC50 [5.9ppm] causing total death of these organisms after seven minutes and one minute, respectively. From this study, both methanol extract and saponins fraction of A. angustifolia leaves have in vitro marked schistosomicidal activity against S. mansoni adult worms with LC50 30 micro g/ml and 11.4 micro g/ ml respectively. Therefore, A. angustifolia may provide a potential source of effective compounds for the control of Schistosomiasis mansoni