Abstract Nervous necrosis virus (NNV) affects more than 177 species of cultured fish including seven band grouper. The present study evaluated the shedding and transmission kinetics of NNV in seven band groupers using a cohabitation challenge model. Initial infection studied by intraperitoneal (IP) injection showed shedding of NNV was acute and peaked within 3–5 days after exposure. This was followed by a post peak period of diminished viral shedding and afterwards an increase in shedding was noticed at 12–16 days in half of the infected fish. In the cohabitation challenge viral shedders used at 10%, 30%, and 50% yielded 20%, 30%, and 100% mortality respectively in naive fish while within-host viral load during the onset of mortality did not show any significant difference across the groups. Peak viral shedding rate was 5.76 × 105 TCID50/L in the 10% shedder group. The other two groups shed at significantly higher than the 10% group with similar rates: 5.82 × 106 TCID50/L in the 30% and 6.1 × 106 TCID50/L in the 50% shedder groups. The empirically derived lowest effective infectious dose of NNV for the bath challenge was 105 TCID50/L. The observations from the present study provide an understanding of NNV shedding kinetics and its transmissibility that assist in better decision making in management of VNN outbreaks.

中文翻译：

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基于腹腔感染-同居模型的七带石斑鱼幼鱼神经坏死病毒感染动力学及脱落动力学

摘要 神经坏死病毒 (NNV) 影响超过 177 种养殖鱼类，包括七带石斑鱼。本研究使用同居挑战模型评估了 7 条带状石斑鱼中 NNV 的脱落和传播动力学。通过腹膜内 (IP) 注射研究的初始感染显示 NNV 的脱落是急性的，并在暴露后 3-5 天内达到峰值。随后是病毒脱落减少的高峰期，然后在 12-16 天时发现一半受感染鱼的脱落增加。在以 10%、30% 和 50% 使用的同居挑战病毒脱落器中，幼稚鱼的死亡率分别为 20%、30% 和 100%，而在死亡率开始期间宿主内病毒载量没有显示出任何显着差异组。病毒脱落率峰值为 5。76 × 105 TCID50/L 在 10% 脱落器组中。其他两组脱落率显着高于 10% 组，脱落率相似：30% 脱落组为 5.82 × 106 TCID50/L，脱落率 50% 组为 6.1 × 106 TCID50/L。根据经验得出的用于沐浴挑战的 NNV 最低有效感染剂量为 105 TCID50/L。本研究的观察结果提供了对 NNV 脱落动力学及其传播性的理解，有助于在 VNN 爆发管理中做出更好的决策。