ABSTRACT: The appearance of infectious hematopoietic necrosis (IHN) virus and the presence of neutralizing antibodies were determined in a population of adult sockeye Oncorhynchus nerka salmon during their spawning migration. Both IHN virus and neutralizing antibodies were detected in sockeye salmon while still in sea water. This is the first reported finding of the virus in wild salmonids in the marine environment and suggests the possibility of a marine host or reservoir. The possibility of vertical or egg-associated transmission was investigated by crossing adults with different titers of IHN virus and also by exposing these gametes to the virus to increase the chances of infecting progeny. Vertical transmission of IHN virus was not observed in eggs or fry from the crosses of IHN infected broodfish, even when eggs were water-hardened in the presence of the virus.

KEY WORDS: Sockeye salmon · Oncorhynchus nerka · Infectious hematopoietic necrosis virus · Vertical transmission · Neutralizing antibodies · Sea water

Published in DAO Vol. 28, No. 1 (1997) on January 16
ISSN: 0177-5103. Copyright © Inter-Research, Oldendorf/Luhe, 1997