Infestation of External Ciliated Protozoan in Red Swamp Crayfish (Procambarus clarkii)

The current study was aimed to investigate ciliated protozoa that can infest Procambarus Clarkii in Assiut governorate, Egypt. Hymenostomatida (Ichthyophthirius multifiliis), Peritrich ciliates (Epistylis sp., Vorticella sp. and Trichodina sp.), Suctorians ciliates (Tokophrya cyclopum, Tokophrya infusionum, Tokophrya quadripartite and Podophrya sp.), Ichthyophonida (Psorospermium haeckeli) and Cyrtophorids (Chilodonella sp.) were all identified from gills, branchiostegite and pleopods of infested individuals. Gills melanization was recorded in 11.5% of infested individuals associated with granulomas or encapsulation reaction filled with hemocytes aggregations (3.84%). Abdomen, pleopods and tail (telson and uropod) were also melanized and covered with brown slime like material in 38.46% of examined samples. Histopathological examination showed lamellar disorganization and distortion of the tip of gills lamellae with vacuoles formation. Hyperplasia and hypertrophied, strongly basophilic nuclei of lamellar epithelial cells and damaged gill lamellae with cuticle lysis were recorded. Lesions of epithelial cells varied from degeneration and necrosis to complete epithelial cell lysis. Melanization and granuloma formation were also recorded. It is obvious from the results that infestation of external ciliated protozoa induced pathogenic lesions in tissue of Procambarus Clarkii