A New Virus Isolated from Salmonid Fish.

Characterisation of a pathogenic virus isolated from marine threadfin fish (Eleutheronema tetradactylus) during a disease outbreak

“…The test was carried out by a modified procedure by Oh et al (1995). Monolayer cultures of BF-2 cells were first exposed to 10 À 4 M IUdR (test cultures), or to MEM-10 (control).…”

“…Samples at the specified times of 0.5, 1, 1.5, 2 and 3 h were removed and rapidly cooled on ice, and the remaining virus infectivity was measured. An aliquot of virus at room temperature (25 jC) was used as a control (Oh et al, 1995).…”

Pathogenicity of the Virus Isolated from Brain of Abnormally Swimming Salmonid.

“…Transmission of IPNV from mature fish to their progeny is known, and the treatment with iodine does not completely inhibit the virus transmission, resulting eggs to become contaminated with IPNV (Wolf et al, 1963, Bullock et al, 1976. The same virus of present one has been isolated from the ovarian fluid of normal mature masu salmon (Oh et al, 1995). If embryos originated from the parental fish infected with this virus are infected with this virus and become persis tently infected, this virus may produce a serious problem in salmon propagation.…”

“…However, the viral infectivity of infected fish, not only dead and/or moribund fish but also survived fish, was not significantly different between waterborne and intramuscular infection. As the present virus manifested persistent infec tion (PI) in some salmonid fish cell lines (Oh et al, 1995), it is suspected that the PI had developed in the tissues of surviving fish. The persistent infection of this virus in vitro requires further study.…”

“…The isolated virus was found not to be related to any known fish viruses. The virus had been detected from both juvenile and adult salmonid, and it is suspected that the virus is wide spread in cultured salmonid of northern Japan (Oh et al, 1995).…”