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

Activity of the plant syzygium jumbos against Biomphularia alexandrina snail's reproduction and infection with schistosoma mansoni

The toxic effects of dry powder water suspension [cold and boiled] and methanol extract of Syzygium jambos leaves determined against Biomphalaria alexandrina snails. Snail's fecundity and their infection with Schistosoma mansoni miracidia were evaluated post exposure to sublethal concentrations of methanol extract. In addition, the activities of aminotransferases [ASAT and ALAT] and phosphatases [AcP and A Ik P] enzymes and total protein levels in tissues of snails under such methanol extract concentrations were detected. The methanol extract was more toxic to the snails than both cold and boiled dry powder water suspension with LC[90]- s 17.9, 876 and 388 ppm respectively, after 24- hr of exposure at 25°C +/- 1. Snails exposed to LC[50] of methanol extract [13.4 ppm] for 24 hours followed by 6 weeks of recovery showed a low survival rate by the 6th week, being 23%. The survived snails laid few eggs, being 1.0 eggs/snail at the 5[th] week. However, no eggs were laid by the 6[th] week. This has a negative reflect on the net reproductive rate [Ro] that was reduced by 74.0%. Twenty-four hours in vivo exposure to the same concentration of methanolic extract [LC[50] caused a significant reduction in the activity of AcP while it increased AlkP, ASAT and ALAT activities in snail's tissues. Infection rate of B. alexandrina snails treated with LC[10] [8.7 ppm] during their exposure to S. mansoni miracidia was significantly less than control group being 32% and 67% respectively. The duration of cercarial shedding was shorter than that of control ones and the cercarial production was significantly reduced being 3209 cercariae/shedding snail compared to 13330 cercariae/control infected snails. From the forgoing data, methanol extract from leaves of the plant S. jambos may be suggested as a promising agent for control of medically important snails may be used as an alternative method to control the size of the populations of B. alexandrina