Attenuation of Infectious Hematopoietic Necrosis Virus (IHNV) and Selection of Low Virulent Clone by Successive Passage and Plaguing

Abstract

A highly virulent strain of infectious hematopoietic necrosis virus (IHNV) was attenuated by successive subculture on several fish cell lines in this study. Consequently, IHNV was attenuated effectively on FHM cell line. An attenuated IHNV clone, AF71-1 was selected from 277 plaque purified clones, which had been isolated from the IHNV subcultured successively for 33 times on FHM cell, by means of infectivity trials to rainbow trout fry. Infectivity trials by both of water born inoculation and intraperitoneal injection with AF71-1 to rainbow trout fry and kokanee fry, revealed that the virulence had been attenuated to remarkably low level as compared with that of the original strain or wild strain of IHNV. © 1989, The Japanese Society of Fisheries Science. All rights reserved.