STUDIES ON THE EFFECT OF CERTAI PHOTOSENSITIZERS ON BIOLOGICAL, BIOCHEMICAL AND HISTOLOGICAL PROPERTIES OF BULINUS TRUNCATUS SNAILS

Abstract

There is no doubt that schistosomiasis is one of the major communicable parasitic diseases with socio-economic and health hazards in the developing world. Controlling the snail intermediate hosts of this parasite by molluscicides is still one of the most promising means in the battle against this parasite.

The present study was planned to evaluate the molluscicidal properties of carbamide perhydrate, copper and magnesium chlorophyllin (Cu-chl and Mg-chl) against Bulinus truncatus snails, the intermediate host of Schistosoma haematobium. Also, snails’ fecundity and infectivity of S. haematobium miracidia to infect these snails and cercarial production from infected ones were determined post snails exposure to the sublethal concentrations of these agents. As well as, some biochemical parameters, e.g. total protein, the activities of AST, ALT and AKP enzymes were evaluated in tissue homogenate of treated snails. Moreover, histological changes in the digestive and hermaphrodite glands and steroid sex hormones were recorded in B. truncatus snails treated with the tested agents.

The data of the present experimental tests are as follow: 1- Carbamide perhydrate was the most toxic agent to B. truncatus snails followed by Mg-chl, while the least toxic one was Cu-chl. Their LC50s were 91.73, 395.1 and 571.4 ppm, respectively. 2- The snail’s fecundity (Mx) and the reproductive rate (R0) of B. truncatus snails were suppressed post 24 hours of maintenance with the three tested agents followed by 4 or 8 weeks of recovery in clean water. The reduction rate of R0 for snails