Schistosomiasis is a one of the most important water-borne trematode diseases which cause health problems. Controlled-release technology was introduced to offer great promise for enhancing the efficacy of some existing active agents and reducing the environmental problems associated with it. The present study aims to utilize controlled release of alginate niclosamide-L-glutamate to control Biomphalaria alexandrina snails as intermediate host of Schistosoma mansoni, as well as to evaluate to what extend it could affect the amount of niclosamide released in relation to attraction and mortality rate of B. alexandrina snails. The results showed that, polymer B3-4b at a concentration of 0.3 ppm niclosamide in combination with 75% L-glutamate caused 100% mortality of Biomphalaria alexandrina snails after 5 days post exposure. More stable Biomphalaria alexandrina snails mortality rate records were obtained after exposure to polymer B3-4a (R2=0.9823) High potential of polymer B3-4a (0.2 ppm niclosamide and 75% L-glutamate) to attract snail toward polymer direction was manifested by 80%, 14%, 6% and 0 snail in area (I), (II), (III), and (IV), respectively after 24 hr post exposure of snail placing at the distal part of aquarium towards the fixed polymer net-bag in area (I). In comparison to other polymers B3-4 showed high mortality rate of attracted snails resembled by 40% and 100% on the 2nd and 7th day, respectively. The present results concluded that modified structure of polymerized niclosamide-L-glutamate, could prolonged the validity of the used chemical. In addition, the steeply released molluscicide enhanced its lower concentrations with increasing concentration of applied attractant that could reduce its toxicity to the water ecosystem. Simultaneously, more efficient snails control at foci transmission could ensure reduction of schistosome infection.
Key words: schistosomiasis, Biomophalaria alexandrina Controlled release, Polymers, Niclosamide, L-glutamate attractant
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