Evaluation of Molluscicidal Activity and Toxicity of some Common Medicinal Plant and Chemical Synthetic Agents against Biomphalaria Alexandrina, the Snail Vector of Schistosoma Mansoni Infection

-This study aims to evaluate and compare the toxicity and molluscicidal efficacy of three monoterpene oils (linalool, thymol, and eugenol) and artemether, plant derivative agents and atrazine, roundup and miltefosine, chemical synthetic agents against freshwater snails Biomphalaria alexandrina ; intermediate host of Schistosoma mansoni . Following WHO guidelines, the sublethal (LC 0 , LC 10 and LC 25 ) and lethal (LC 50 and LC 90 ) concentrations of tested materials were estimated after 24 hours exposure followed by another of recovery. The recorded results illustrated that all the tested agents had molluscicidal properties and a toxic effect against the examined snails. The most potent molluscicidal agent was atrazine expressed by LC 50 of 1.31 ppm and LC 90 of 4.07 ppm followed by roundup with LC 50 3.21 ppm and LC 90 12.61ppm, then miltefosine with LC 50 14.66 ppm and LC90 24.06 ppm, then artemether with LC 50 18.30 ppm and LC90 28.40 . Furthermore, the recorded results showed that the molluscicidal activity of the tested agents was arranged according to their lethal concentrations against B. alexandrina snails as the following: atrazine > roundup > miltefosine > artemether > thymol > eugenol > linalool. This study highlights plant derivative agents as safe natural molluscicides instead of harmful toxic chemical synthetic agents on non-target organisms and even man. It is recommended that more research studies should be carried out to assess the impact of linalool, thymol, eugenol and artemether in terms of biological, biochemical and molecular parameters of snails as well as their efficacy as schistosomicidal agents against S . mansoni worms.