Fate of Betanodaviruses in the Experimentally Infected Natural and Non-Natural Host

Abstract

To investigate the fate of betanodavirus, the causative agent of viral nervous necrosis (VNN) in cultured fish, the tissue distribution of virus in experimentally infected fish was investigated. Two genetically different betanodaviruses, striped jack nervous necrosis virus (SJNNV; SJNNV-genotype) and kelp grouper nervous necrosis virus (KGNNV) belonging to red spotted grouper nervous necrosis virus (RGNNV)-genotype, were intramuscularly cross-injected with a dose of 10⁶ TCID₅₀/fish/200 μl in striped jack Pseudocaranx dentex or kelp grouper Epinephelus moara and sacrificed at scheduled to titre the virus in the spinal cord, brain, eye, kidney and blood at day 0, 1, 3, 5, 14 and 21. As a result, intramuscularly inoculated virus was recovered at high titres from the brain, spinal cord, and eye of their natural host species, i.e., striped jack for SJNNV and kelp grouper for KGNNV during 3-week experimental period, while the virus titres were relatively low in the organs of non-natural hosts, particularly in kelp grouper injected with SJNNV. In every case, no virus was detected in blood samples, suggesting that infection did not develop to be systemic.

Keywords: Betanodavirus, Viral nervous necrosis, Fate, Tissue distribution, Pseudocaranx dentex, Epinephelus moara, 50% tissue culture infectious dose (TCID₅₀)

DOI: http://dx.doi.org/10.3329/bjm.v24i2.1252

Bangladesh J Microbiol, Volume 24, Number 2, December 2007, pp 100-104