RESUMEN
It was found that the exposure of B. alexandrina to LC25 of fungicide [Isoprothiolane], herbicide [Anilofos] and plant extract [Euphorbia lactea] led to a highly significantly elevation in the number of abnormal egg masses laid by treated snails in comparison with the control ones. The LC25 caused reduction in infection rate of B. alexandrina. It caused reduction in number of cercariae per snail during the patent period and reduction in the period of cercarial shedding. The results showed that adenosine triphosphatase [ATPase] activity of tissue of snails was significantly increased in response to tested substances. The activity level of lactate dehydrogenase [LDH], pyruvate kinase [PK] and phosphoenolpyruvate carboxy kinase [PEPCK] was significantly reduced in response to the treatment. This reduction did not reflect on both D. lactate and pyruvate concentrations