Hirudinicidal activities of some natural molluscicides used in schistosomiasis control.

Experiments were conducted with (molluscicides) aridanin isolated from Tetrapleura tetraptera, aridan, an extract from T. tetraptera, endod, an extract from Phytolacca dodecandra and niclosamide on non-target aquatic organisms such as leech, hydra, tadpoles, anopheline mosquito larvae and brine shrimps and compared with their toxicity to the target snail. Biomphalaria glabrata. Aridanin, aridan, endod, and niclosamide produced rapid knockdown effects on B. glabrata at 0.04, 1.00, 30.00, and 40.00 ppm, respectively. All the molluscicides killed the leech, a pest of animals and man at molluscicidal concentrations. The hydra and tadpoles tested were sensitive to the molluscicides except aridanin but the shrimps and anopheline mosquito larvae were resistant to all the molluscicides.