The research on pathogenicity of fish nervous necrosis virus to Rachycentron canadum juvenile
鱼类神经坏死病毒对军曹鱼仔鱼的致病性

In this paper, the pathogenicity of fish nervous necrosis virus to Rachycentron canadum juveniles was studied by observations of the mortality and histo-pathological changes through three infected routes including intramuscular injection (IM), bath exposure and cohabitation. The results showed that the juveniles infected with NNV manifested the typical symptom such as severe sickness with anorexia, pale-grey pigmentation of body and whirling swimming. And the cumulative mortalities of infected fish via IM injection, bath exposure infection and cohabitation were 78%, 44% and 34%, respectively. NNV could be detected in the brain, eye and spinal cord of the infected R. canadum juveniles with RT-PCR at 18h post-IM injection. Microscopic observation revealed vacuolations in brain, retina and spinal cord of the infected juveniles. So the results demonstrated that R. canadum juveniles were susceptible to nervous necrosis virus and the virus could transmit horizontally among the juveniles by water.