Histopathological evaluation of Wallago attu (Bloch & Schneider, 1801) infested by ectoparasites

Abstract

Abstract Background Host-parasite interaction studies represent the dependency of the parasites on the host through various models. Gill infesting copepods, monogeneans and isopods served as excellent models to study the details of host-parasite interaction. In the present investigation, Wallago attu (Bloch & Schneider, 1801) was extensively studied for histopathological damage caused by ectoparasites like monogeneans (Thaparocleidus indicus, Thaparocleidus wallagonius and Mizelleus indicus), copepod (Ergasilus malnadensis) and an isopod (Alitropus typus) during August 2017 to February 2018. Both the control (least infested) and severely infested gills were examined through light microscope to approximate the intensity of damage caused by above ectoparasites. Results Pathological effects of ectoparasites displayed a fusion of secondary lamella, hyperplasia of the gill filaments and the epithelial cells, propagation of bronchial tips, thinning of the central axis, deshaping, shortening and fusion of secondary gill lamellae epithelium, severe degenerative and necrotic changes in gill filaments and secondary lamellae, curling of secondary lamellae and mucous cells proliferation. Conclusions Ectoparasites cause severe damage to gills of W. attu, thereby diminishing the gill breathing capacity of the fish. Timely pathological studies can reveal the extent of damage caused by the parasites and thus various diagnostic programs and best management practices can be implemented in aquaculture for the better yield.

Keywords

• Copepods
• Gills
• Histopathology
• Host-parasite interactions
• Isopods
• Microscopy