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

Efficacy of temperature, and two commonly used molluscicides and fertilizers on fasciola gigantica eggs

This study .evaluated the effect of temperature, molluscicides [Copper sulphate and Niclosamide], fertilizers [Superphosphate and Ammonium sulphate] on the hatchability of Fasciola gigantica eggs. The results showed that hatchability decreased to 4% when eggs were incubated in bile secretion at 37°C for 5 days and to 1.4% for 10 days, but few eggs incubated in water at 37°C hatched. Bile secretion at 37°C was a poor medium for in-vitro egg preservation. But, hatching occurred only when eggs were transferred to water at 26°C. Temperature fluctuation from 26-4°C or from 32- 4°C had an inhibitory effect on embryos development [35.2% and 32.3%, respectively] as compared to controls [60% and 63.9%, respectively]. The incubation period [19 and 17 days] was higher than controls [14 and 12 days, respectively]. The LC50 and LC9o of Copper sulphate and Niclosamide against Biomphalaria alexandrina and Lymnaea natalenesis had no toxic effect on Fasciola eggs. The higher concentrations of Copper sulphate [30ppm] and Niclosamide [Ippm] slightly lower eggs hatchability rate than controls. The rate decreased by increasing the exposure time from 3 to 6 hours with both molluscicides. Ammonium sulphate had a lethal effect on eggs, but Superphosphate had some inhibitory effect on egg development, which increased by increasing Superphosphate concentration or with the prolongation of the exposure time

Clinico-pathological and histological observations in Oreochromis niloticus exposed to the molluscicidal activity of Anagallis arvensis

The exposure of Nile tilapia [Oreochromis niloticus] to dry powder suspension of Anagallis arvensis at concentrations of 50 ppm and 100 ppm for 24 and 48 hours was considered to study the reaction of this fish against the used plant. A. arvensis was previously succeeded as an effective molluscicide for the control of Schistosoma and Fasciola snails. The present study aimed to test the effect of the molluscicidal doses of Saboon El-Gheit [A. arvensis] on some serum parameters and some tissue histopathological observations of O. niloticus to clarify whether this plant is safe, nontoxic and fit for this type of fish or not. O. niloticus exposed to the plant suspension showed no clinical symptoms and no patho-anatomic signs externally or internally after the exposure periods and at sampling. The results revealed that the dry powder suspension of A. arvensis at molluscicidal concentrations has neither toxic nor hazardous effects for O. niloticus