Histological changes in skin and gill of fresh water EUS infected fish Channa punctatus

Abstract

Histopathology is an important diseases diagnostic tool. Penetration into the host is the first step for a microbial agent to mutiply and invade the vital organs of its host. Like all animals fishes suffers from environmental, stress, which is followed by pathogenic attacks and parasitic afflictions causing Epizootic Ulcerative syndrome (EUS). Histological investigations of tissues of EUS infected fish Channa punctatus showed an eroded epidermis, necrosis of skeletal muscles and intense granulomatous inflammation, infiltration of mixed inflammatory cells in muscular as well as submuscular layers of the skin. Also a characteristic focal grannular granuloma in the gill lamellae was noticed. The electron microscopic observations, of the tissue cells of the fishe showed viruses like Parvovirus even at a red spot stage. Thus, it can be said that Viruses being crystalline in nature have cellular penetrating power & the EUS infection follows the phyllogenetic evolution in life in true sense i.e. RNA virus followed by Bacterial cell and then Fungus. Thus, the presence of EUS in Channa punctatus is confirmed histologically.