Characterization of Herpes virus vitreum isolated from hyperplastic epidermal tissue of walleye, Stizostedion vitreum vitreum (Mitchill)*

Abstract

A new virus, provisionally named Herpesvirus vitreum, was isolated from hyperplastic epidermal tissue from a walleye, Stizostedion vitreum vitreum (Mitchill), taken in Saskatchewan, Canada. The virus, which was isolated in the walleye ovarian (WO) cell line, was identified as a herpesvirus on the basis of size (190-230 nm), morphology and apparent pattern of replication. The virus, which passes polycarbonate membranes of 200 nm mean pore diameter, was ether-labile. Virus replicated in WC-1 cells at 4 and 15X, but not at 20 C. Although walleye cell lines (WO, WC-1, We-2) were susceptible to infection at 15 C, non-percid cell lines were refractory. Syncytial formation and lysis occurred in susceptible cell lines. Virus was quantified by plaque assay at 13 to 15 C for two weeks. Replication was inhibited by IO'^-'^M phosphonoacetate and by lO"^-*^ M 5-bromodeoxyuridine (BUDR), but addition of excess thymidine reversed the inhibition by BUDR. Viral replication in WO cells, but not in WC-1 cells, was inhibited by the antiherpetic drug acyclovir (10"^-" M). The relationship of the herpesvirus isolate and epithelial neoplasms was not determined.

Morphological differentiation of virus-associated skin tumors of walleye (Stizostedion vitreum vitreum).

“…The tumors are lymphocystis and dermal sarcoma described earlier (YAMAMOTO et al, 1976) and two types of epidermal hyperplasias-one de scribed as a diffuse form and the other described as a discrete form. The analysis of thin-sections re vealed the association of a lymphocystis virus and a retrovirus (YAMAMOTO et al, 1976); a herpesvirus (KELLY et al, 1980(KELLY et al, , 1983, and a different retro virus (unpublished observation) for the respective tumors. The physical appearance, histological na ture and electron microscopic observations are described.…”

“…A summary of the four different growths on the skin of walleye together with their associated viruses is summarized in Table 2. The initial virus propagation in cell culture from an epidermal hyperplasia was a herpesvirus (KELLY et al, 1980(KELLY et al, , 1983. However electron microscopic analysis showed that another epidermal hyper plasia-the discrete form was more common.…”

“…In central Canada at Crean Lake, Saskatchewan, YAMAMOTO et al (1976) observed the occurrence of lymphocystis and dermal sarcoma in spawning walleye. Several years later KELLY et al (1980KELLY et al ( , 1983 reported the propagation of a herpes virus from extracts of walleye epidermal hyperplasia taken from a similar lake. That there exists a second form of epidermal hyperplasia has been noted and its report is in press (YAMAMOTO et al, 1985).…”

Virus-associated epidermal hyperplasia in golden ide Leuciscus idus meianotus

“…Temperature-dependent replication of herpesviruses of fish has been observed. Herpesvirus vitrieum from hyperplastic epidermal tissue of walleye Stizostedion vitreum vitreum replicated at 4 and 15 "C but not at 20 " C , a temperature most suitable for walleye ovary (WO) cell growth (Kelly et al 1983).…”

Characterization of A Herpes-like Virus Isolated from Cultured Japanese Eels in Taiwan.

“…These viruses include channel catfish virus (CCV) (Wolf and Darlington, 1971), Herpesvirus sal monis (Wolf et al, 1978), NeVTA (nerka virus of Towada Lake, Akita and Aomori) (Sano, 1976), Oncorhynchus masou virus (OMV) (Kimura et al, 1981), yamame tumor virus (Sano et al, 1983), Herpesvirus vitreum (walleye herpesvirus) (Kelly et al, 1983), Herpesvirus cyprini (Sano et al, 1985) and Herpesvirus anguillae (Sano et al, 1990). Among these viruses, CCV, NeVTA, YTV, OMV and CHV were experi mentally demonstrated to be able to produce high mortality rate among inoculated fish.…”