ABSTRACT
The survival rate and fecundity of B. Alexandrina were greatly influenced when exposed to either S. mansoni or E. Liei miracidia. The snails exhibited much lower survival rate and fecundity when double exposed to both S. mansoni and E. liei miracidia than single exposure and control snails. The results indicated a disruption in the snail metabolism due to the exposure to S. Mansoni and E. Liei miracidia and this effect was more pronounced in case of double exposure to the two parasites. Protein concentrations in hemolymph and tissues were significantly reduced in all exposed snail groups than in the control group. A significant elevation in the levels of aspartate aminotransferase [ASAT] and alanine aminotransferase [Asat] enzymes was recorded in hemolymph and tissues of exposed snail than the unexposed control snails. The ASAT/ALAT ratios in tissue and hemolymph of single- exposed and unexposed B. Alexandrina did not exceed 1, while it increased up to 1.18 in hemolymph of double exposed snails. There were significant increases in the levels of acid and alkaline phosphatases enzymes in the exposed snails