Ultrastructural studies on intestinal response of carp, Cyprinus carpio L., to the pseudophyllidean tapeworm, Bothriocephalus acheilognathi Yamaguti, 1934

The pathological effects of Bothriocephalus acheilognathi on the gut of experimentally infected carp, Cyprinus carpio L., have been studied. Light and electron microscopical observations revealed that damage to the host gut was not restricted to the area engulfed by the bothria, and loss of gut microvilli and the separation and shedding of enterocytes occurred against the site of attachment. Lymphocytes, macrophages and eosinophils accumulated in the wall of the infected gut and migrated into the lumen where they adhered to the parasite tegument. The role of parasite‐derived and host‐produced factors in leucocyte migration and attachment to the worm are discussed.