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 15°C, but not at 20°C. Although walleye cell lines (WO, WC-1, We-2) were susceptible to infection at 15°C, non-period 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 10^-3.0m phosphonoacetate and by 10^-5.0m 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^-5.0m ). The relationship of the herpesvirus isolate and epithelial neoplasms was not determined.