Viral hemorrhagic septicemia virus (VHSV) is an ongoing cause of disease and mortality in freshwater fishes across the Great Lakes region of the Midwestern United States. Antibody detection assays such as enzyme-linked immunosorbent assay (ELISA) are nonlethal serological methods that can have significantly shorter turnaround times than the current validated viral detection diagnostic methodology for VHSV: cell culture with confirmation by polymerase chain reaction (PCR). This study evaluated an ELISA that detects nonneutralizing antinucleocapsid antibodies to VHSV in Northern Pike Esox lucius. Juvenile Northern Pike were experimentally infected with VHSV by intraperitoneal injection. The infected fish were monitored for 12 weeks for signs of disease, and weekly serum samples were obtained. An analysis of the survival data showed that mortality occurred significantly more quickly in inoculated fish than in control fish. Fish that were infected by injection showed a significant increase in antibody response by 2 weeks postinfection. However, variation in the rate and pattern of antibody response among the infected fish was high at any given point. The optimum window for detecting antibodies in Northern Pike is 2-12 weeks postinfection, which generally follows the median time to appearance of clinical signs (21 d postinfection). The receiver-operating characteristic curve analysis showed the ELISA to have a sensitivity of 80.5% and a specificity of 63.2% in Northern Pike, but these values can be adjusted by choosing different percent inhibition cutoffs, which may facilitate the use of the test for specific management goals. The results of this study offer insights into the disease progression and immune kinetics of VHSV, including interindividual variation, which will aid in the management of this economically important virus.

中文翻译：

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病毒性出血性败血症病毒实验性感染北梭鱼的血清学诊断试验和抗体发育动力学评估

病毒性出血性败血症病毒 (VHSV) 是美国中西部五大湖地区淡水鱼疾病和死亡的持续原因。酶联免疫吸附测定 (ELISA) 等抗体检测测定是非致死性血清学方法，其周转时间比目前已验证的 VHSV 病毒检测诊断方法短得多：细胞培养通过聚合酶链反应 (PCR) 进行确认。本研究评估了一种 ELISA，该 ELISA 检测可检测 Northern Pike Esox lucius 中针对 VHSV 的非中和性抗核衣壳抗体。幼年北梭鱼通过腹腔注射实验性地感染了 VHSV。监测受感染鱼的疾病迹象 12 周，每周采集血清样本。对存活数据的分析表明，接种鱼的死亡率明显高于对照鱼。通过注射感染的鱼在感染后 2 周显示抗体反应显着增加。然而，在任何给定时间点，受感染鱼的抗体反应率和模式变化很大。在 Northern Pike 中检测抗体的最佳窗口是感染后 2-12 周，这通常是出现临床症状的中位时间（感染后 21 天）。接受者操作特征曲线分析显示 ELISA 在 Northern Pike 中具有 80.5% 的灵敏度和 63.2% 的特异性，但这些值可以通过选择不同的抑制百分比截断值来调整，这可能有助于使用特定的测试管理目标。