Occurrence and Pathology of Ligula intestinalis Infections in British Fishes

Abstract

Infection of British freshwater fishes with the plerocercoid larva of L. intestinalis is most widespread and common in the roach. It is less common in gudgeon, rudd, bream, and minnow, and rare in dace. Roach fry may become infected within the first 3 months of life. Infections in roach exceeding 13 cm in length are infrequent. Data concerning the size distribution of pleroceroids in fish of different size are given. In infected roach, the liver weight, packed cell volume of erythrocytes and hemoglobin are reduced. Gonadal retardation is a universal consequence of infection. It is severe in roach, rudd, bream, dace, and minnow but is less marked in gudgeon.