Summary :Epidemiological investigations on Fasciola hepatica fasciolasis were carried out from July 2004 to June 2005 in the Gafsa oases (Tunisia) after the detection of a human case. Three habitats were studied: one in El Gsar and two in Ain Soltan. The prevalence of human infection was 6.6 %. The presence of the parasite was detected through serology in 14.

Context: The persistence of fascioliasis in many developing countries urges the search for simple, cheap, and effective substances. In this view, plants provide interesting molluscicidal activities thanks to the secondary metabolites they produce. The genus Solanum is known for its potent effect on vector snails. Materials and methods: Solanum elaeagnifolium seeds were powdered and successively extracted using n-hexane, methylene chloride, acetone, and methanol, for 20 h each. After filtration, solvents were evaporated. An acid-base treatment was conducted on seed methanolic extract to isolate total alkaloids and b-solamarine. Total saponins fraction was obtained after successive macerations and evaporations. The molluscicidal activity was evaluated by subjecting snails, in groups of 10, for 48 h to 500 mL of extracts, fractions, and pure product aqueous solutions, each containing amounts, ranging from 1 to 50 mg of plant material in 5 mg increments. Results: The methanolic extract of seeds, b-solamarine isolated for the first time from this plant and total saponins fraction showed very potent activities on snails, giving respective median lethal concentrations (LC 50 ) of 1.18, 0.49, and 0.94 mg/L. Total alkaloids fraction obtained from the methanolic extract was less active giving an LC 50 value of 14.67 mg/L. Discussion and conclusion: This study emphasizes that glycoalkaloids and saponins of Solanum elaeagnifolium are potent molluscicidal agents. Seed methanolic extract, b-solamarine, and total saponins fraction may be used as molluscicides.

Fasciolosis is a widespread parasitosis of farm live-stock in many developing countries. For this reason, it is necessary to search for new substances against parasitic diseases caused by flukes. Indeed, a wide variety of terrestrial plants have been subjected to chemical and pharmacological screening in order to discover their potential for human medicinal use. The molluscicidal and larvicidal activities of Atriplex inflata were tested on Galba truncatula and Fasciola hepatica larval stages infecting this snail in Tunisia. Phytochemical tests were conducted on extracts in order to establish a meaningful relationship with molluscicidal and larvicidal activities. The molluscicidal activity was evaluated by subjecting snails to sample aqueous solutions. Accordingly, hexane, ethyl acetate, methanol and methanol-water (8:2, v-v) were used as extraction solvents. As a result, hexane and ethyl acetate extracts showed potent activity, according to the World Health Organization, giving LC50 = 7.59 mg/L and 6.69 mg/L for hexane extracts of leaves and fruits, respectively. Ethyl acetate extracts gave LC50 = 5.90 mg/L and 7.32 mg/L for leaves and fruits, successively. Molluscicidal activities of powders were less potent on snails, but active according to the World Health Organization. Hexane and ethyl acetate extracts from leaves and fruits gave potent larvicidal activities with a delay rate exceeding 45.50% (45.50- 98.92%). Phytochemical tests showed that these activities may be attributed to the presence of triterpenoids and/or sterols.

Monthly samples of Bulinus truncatus were collected during a year from a cattle-breeding farm located in the region of Sejnane (North Tunisia) to detect natural infections with Fasciola hepatica and determine seasonal variations of the prevalence throughout a year. Of the 163 adult bulinids, larval forms of F. hepatica were found in 39% of snails. Two peaks in prevalence, the first in June and the second in October, were also noted. Bulinus truncatus can be added to the list of potential intermediate hosts of F. hepatica.

The ethyl acetate extract and both pure compounds proved the highest larvicidal activities, with a deterioration rate exceeding 89.2% (89.2-100%) and with no toxic effects against associated fauna. © 2016 Society of Chemical Industry.