[The action of fenasal on the ultrastructure of the tegument in Caryophyllaeus laticeps cestodes].

The effect of the anthelmintic preparation fenasal on the fine structure of tegument of the cestode Caryophyllaeus laticeps, a parasite of Cyprinidae, was studied in vitro. 10 mcg/ml concentration of fenasal causes numerous evaginations of the external cytoplasmic layer in the scolex of helminth. Inside these formations there are granules of secretion, mitochondria, vacuoles. At the same time microtrichia disappear from the surface, cytoplasmic layer gets thinner and its mitochondria degenerate. In the middle part of the body the number of microtrichia decreases, the layer of tegumental cells swells and conformational condition of its mitochondria changes. The degree of injury depends on the exposition time which was from 0 to 4 hours.