PATHOGENICITY OF THE CAUSATIVE AGENT OF VIRAL NERVOUS NECROSIS DISEASE IN STRIPED JACK, PSEUDOCARANX-DENTEX (BLOCH AND SCHNEIDER)

The pathogenicity of the agent causing viral nervous necrosis (VNN) of striped jack, Pseudocaranx dentex (Bloch & Schneider), was examined i n striped jack and other selected marine fish species. Fish were expos ed to purified striped jack nervous necrosis virus (SJNNV) (0.1-100 ng ml-1) or homogenates of diseased striped jack larvae. Striped jack la rvae (3.5 and 4.4 mm total length) were susceptible to the virus, but juveniles (78 mm) were not. The viral antigens were detected by indire ct ELISA and the characteristic pathological changes, i.e. vacuolation in the retina and brain, were reproduced in the affected larvae. The infection was also established in healthy larvae by cohabitation with the diseased larvae. Larvae of red sea bream, Pagrus major Temminck & Schlegel, yellowtail, Seriola quinqueradiata Temminck & Schlegel, and goldstriped amberjack, Seriola lalandi Valenciennes, were not suscepti ble to SJNNV.