New approach to control of fasciolosis: Neutralization of Fasciola hepatica miracidia with methanol extracts of three Artemisia species at preserved vitality of Galba truncatula snails

Fasciola hepatica is a causative agent of fasciolosis, a widespread parasitosis with a significant negative effect on the livestock industry. The disease is controlled through drug treatment of farm animals with synthetic anthelmintics. Two hosts and free-living stages are included in the parasitic life cycle - definitive (grazing animals, humans) and intermediate (freshwater snails), providing the multiplication of the larvae.  The infected animals produced the parasite eggs, passed with the faces. Falling into an aquatic environment the eggs hatched the miracidia - the swimming larvae infecting snails after active penetration through the snail body surface.

The targeted miracidial treatment can be an opportunity for the control of fasciolosis. In this study, the effectiveness of the methanolic extracts of Artemisia absinthium L., Artemisia lerchiana Stechm and Artemisia santonicum L. (Asteraceae) were examined for anti-miracidial and molluscicidal action. The chemical composition of the studied extracts and fractions were analyzed by gas chromatography-mass spectrometry (GC-MS) and high-performance thin-layer chromatography (HPTLC). Plant material was collected from the natural localities of the studied species. Phenolic acids (chlorogenic, 4(p)-hydroxybenzoic, vanillic and quinic), flavonoid aglycones (artemetin - quercetagetin 3,6,7,3',4'-pentamethyl ether), fatty acids (linoleic acid, C18:2 as dominant) were identified in the extract of A. absinthium. A. santhonicum and A. lerchiana belong to Artemisia maritima group and have similar chemical profiles. However, a few differences were found in the extracts. Multi-component flavonoid profiles of both species were detected. Highly methylated flavonoid aglycones derivatives of quercetagetin, apigenin, and luteolin were identified. The high content of unsaturated fatty acids (C18:3, C18:1, C18:2) was found, too. Also chlorogenic, quinic, azelaic, protocatechuic, and caffeic acids as well as polyols, triterpenes were established in the extracts.

F. hepatica miracidia and G. truncatula snails were obtained from the laboratory maintained life cycles. Three groups of 100 miracidia and 10 snails each were constituted per treatment. Each snail was individually exposed to 10 freshly hatched miracidia in 3 ml water in the absence (control) or presence of Artemisia  extracts at final concentrations of 50, 100 to 200, and 400 mg/ml, for 2 h (exposure period), at room temperature.

The obtained results clearly showed the effectiveness of used concentrations of Artemisia extracts on the viability of invasive larvae of the parasite and its intermediate snail host.

Here, we presented preliminary data for neutralization of F. hepatica miracidia with plant extracts at preserved vitality of G. truncatula snails - these results have a potential value for future application and outlined a new approach to the control of fasciolosis.