Effect of three dopmant oil on schistosomiasis and fascioliasis vector snails and its relation with some non traget snails

ABSTRACT

Three oils were tested for their molluscicidal activity, Caple-2, Kemasol and super-max. super-max had the strongest toxic effect on B. alexandrina and other snail species. Its LC50 was 0.53 ppm, meanwhile LC50 of kemasol 3.2 ppm and 4.21ppm for Caple 2. the LC50 and LC90 of the oils were lower in lymneae natalensis as compared to B. alexandrina. The LC50 and LC90 of the oils against non-target snails [physa acuta, Helisoma duryi,planorbis planorbis and melanoides tuberculata] were higher as compared to B. alexandrina. Hatchability of snails' eggs exposed to super-max [3.0 and 5.0 ppm] was stopped completely and 1.0 ppm showed the lower percent of egg hatchability 22.7%. Caple 2 kemasol did not affect eggs hatchability. Super-max had the strongest harmful effect on both miracidia and cercarias of S. mansoni.100% mortality values were obtained for both larval stages after 8 and 9 minutes respectively when maintained at LC50. 100%mortality of miracidia occurred after 35 and 155 minutes when maintained at LC50 of kemasol and caple 2 respectively. The infection rate of B. alexandrina with S. mansoni miracidia was greatly reduced by the sublethal concentrations of the oils. The reduction of infection rate was higher in snails treated with supermax [42.9%].A highly significant reduction of total cercarial production per snail was in the experimental groups as compared with control. The prepatent period of treated snails was prolonged compared to control. Moreover, Total protein content and enzyme activities of snails treated with LC10 of oils showed a significant reduction as compared with control in the haemolymyph. there was an increase of protein control in haemo-ALKP enzyme activity was slightly increased in haemolyph of experimental groups than controls and was significantly higher in the tissues as compared to control. ALT enzyme activity in haemolymph of experimental groups was higher than control but lower in tissue. AST enzyme activity was higher in haemo- lymph and tissue of experimental groups than control. The SDS-PAGE pattern of tissue proteins from treated B. alexandrina and controls showed different oils effects on the synthesis of within snails yielded a complex pattern of polypeptides ranging in molecular weight between 13.775 to 156.7 kDa. Many bands were present in treated snails. AT least, one band was detected for snails treated with each of the oils and not in controls. The difference in the similarity in- dices between treatment and control; for kemasol was 0.86 and 0.64, for caple 2 was 0.61 and 0.55 and for supermax was 0.64 and 0.86. LC25 of supermax did not cause any mortality to daphnia after 6 hr. but, LC50 and LC90 caused lower mortality after 6 hr. kemasol caused 100% mortality after 4 hr at LC50 and 2 hr in LC90. caple 2 caused 50% mortality of daphnia after 5 hr at LC25 and 100% mortality after 30 minutes in LC50 and LC90.