Pathogenicity of a marine birnavirus (AY-98) isolated from diseased ayu Ple
coglossus altivelis was investigated. Cumulative mortalities in the intrape
ritoneally injected groups of ayu in two weeks were 70% (dose 10(5.4) TCID5
0/fish)-71%(10(5.8) TCID50/fish) in duplicated experiments. Histologically,
the naturally and experimentally infected fish showed brain congestion and
pancreatic necrosis. From the symptoms of body deformity and congestion in
the brain, it was thought that AY-98 is similar to viral deformity virus,
the birnavirus isolated from yellow tail Seriala quinqueradiata with deform
ity.