Garver Kyle A, Batts William N, Kurath Gael
a Department of Pathobiology , University of Washington , Seattle , Washington , 98195 , USA.
b U.S. Geological Survey, Biological Resources Discipline, Western Fisheries Research Center , 6505 Northeast 65th Street , Seattle , Washington , 98115 , USA.
J Aquat Anim Health. 2006 Dec;18(4):232-43. doi: 10.1577/H05-038.1.
Infectious hematopoietic necrosis virus (IHNV) is an aquatic rhabdovirus that infects salmonids in the Pacific Northwest of the United States, Europe, and Asia. Isolates of IHNV have been phylogenetically classified into three major viral genogroups, designated U, M, and L. To characterize virulence of IHNV in the context of these three viral genogroups, seven strains of IHNV (three U genogroup strains, three M strains, and one L strain) were compared for their pathogenicity in juvenile sockeye salmon Oncorhynchus nerka, kokanee (lacustrine sockeye salmon), and rainbow trout O. mykiss. Fish were waterborne-exposed to the different viral strains, and virulence was assessed by comparing mortality curves and final cumulative percent mortality (CPM) in both species of fish at 10°C and 15°C. In sockeye salmon and kokanee, the U genogroup virus types were extremely virulent, causing average CPMs of 69-100%, while the M genogroup virus types caused very little or no mortality (CPM = 0-4%). The endangered Redfish Lake sockeye salmon stock exhibited extreme differences in susceptibility to the U and M genogroups. Conversely, in two stocks of rainbow trout, the M genogroup virus types were more virulent, inducing average CPMs of 25-85%, while the U genogroup viruses caused lower mortality (CPM = 5-41%). In both fish species, the single L genogroup strain caused low to intermediate mortality (CPM = 13-53%). Viral glycoprotein sequence comparisons of the seven challenge strains revealed three amino acid sites (247, 256, and 270) that consistently differed between the U and M genogroups, possibly contributing to pathogenicity differences.
传染性造血器官坏死病毒（IHNV）是一种水生弹状病毒，可感染美国太平洋西北部、欧洲和亚洲的鲑科鱼类。IHNV的分离株在系统发育上已被分为三个主要病毒基因组，分别命名为U、M和L。为了在这三个病毒基因组的背景下表征IHNV的毒力，比较了七株IHNV（三株U基因组菌株、三株M菌株和一株L菌株）对幼年红大马哈鱼（Oncorhynchus nerka）、红大麻哈鱼（湖泊型红大马哈鱼）和虹鳟（O. mykiss）的致病性。将鱼通过水接触暴露于不同的病毒菌株，并通过比较10°C和15°C下两种鱼类的死亡率曲线和最终累积死亡率（CPM）来评估毒力。在红大马哈鱼和红大麻哈鱼中，U基因组病毒类型极具毒性，平均CPM为69 - 100%，而M基因组病毒类型几乎不引起死亡或不引起死亡（CPM = 0 - 4%）。濒危的红鱼湖红大马哈鱼种群对U和M基因组的易感性表现出极大差异。相反，在两株虹鳟种群中，M基因组病毒类型毒性更强，诱导的平均CPM为25 - 85%，而U基因组病毒引起的死亡率较低（CPM = 5 - 41%）。在两种鱼类中，单一的L基因组菌株引起低至中等死亡率（CPM = 13 - 53%）。对七株攻击菌株的病毒糖蛋白序列比较揭示了U和M基因组之间始终存在差异的三个氨基酸位点（247、256和270），这可能导致致病性差异。
