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

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.