CARP COCCIDIOSIS - INTESTINAL HISTOPATHOLOGY AND CYTOPATHOLOGY UNDER GOUSSIA-CARPELLI INFECTION

The tissue response of carp Cyprinus carpio to the coccidian parasite Goussia carpelli (Leger & Stankovitch, 1921) was investigated during a laboratory infection by histological and electron microscopical techn iques. During merogonic and early gamogonic development severe damage to infected epithelial tissue was observed, resulting in extensive los s of epithelium and damage to the lamina propria. In heavily infected carp, the most severe damage was observed in late merogony and early g amogony at about Day 9 post exposure, when the epithelium was destroye d with the exception of some remnants deep between mucosa folds. As a repair mechanism of destroyed tissue, areas of naked propria became co vered by broad, plain cells of a squamous epithelium within a few days . Enterocytes harbouring G. carpelli oocysts were observed to migrate into subepithelial tissue. Phagocytic activity was seen in all granulo cyte types in the gut. Compared to coccidia of birds and mammals, the tissue damage caused by G. carpelli indicated high pathogenic capacity . The weak clinical symptoms of this coccidiosis might be explained by the rapid repair of destroyed tissue and the absence of dehydration i n freshwater fishes.