Department of Aqualife Medicine, Chonnam National University, Yeosu, 59626, Republic of Korea.
Department of Aqualife Medicine, Chonnam National University, Yeosu, 59626, Republic of Korea.
Virus Res. 2019 Jul 2;267:16-20. doi: 10.1016/j.virusres.2019.05.001. Epub 2019 May 2.
Viral hemorrhagic septicemia (VHS) is a cold-water disease caused by viral hemorrhagic septicemia virus (VHSV) at an optimal temperature of 9 °C-15 °C. VHSV isolation and detection have been accomplished by using a number of diagnostic methods such as cell culture and qRT-PCR. Spleen and kidney have been reported as the main target organs of VHSV-infection; however, how VHSV spreads throughout the fish body has not been clearly studied. The purpose of this study was 1) to investigate viral titer and viral RNA copy number in the blood of VHSV-infected olive flounder at 10 °C and 13 °C; 2) to compare VHSV titer and viral RNA copy numbers in blood from fish exposed to the virus by two different challenges. VHSV titer at 10 °C was higher than at 13 °C in blood samples of injection challenged group. Whereas, similar titer was observed at 10 °C and 13 °C in the blood samples of the immersion challenged group. At 10 °C, copy numbers of VHSV-N gene in blood of immersion challenged group increased slightly in comparison to injection challenged group. At 13 °C, similar patterns were observed between the injection and immersion challenged groups. Also, higher titer and copy number were observed in fish blood compared to tested organs from our previous study. Our results indicate that VHSV genome existed in fish blood at earlier time points after infection, and the blood may contribute to the spread of the virus in whole fish body. In addition, VHSV diagnosis by qRT-PCR from fish blood samples, not requiring sacrificing the host fish can be valuable to collect the kinetic information of viral infection.
病毒性出血性败血症（VHS）是一种冷水病，由最佳温度为 9°C-15°C 的病毒性出血性败血症病毒（VHSV）引起。已经使用多种诊断方法（如细胞培养和 qRT-PCR）完成了 VHSV 的分离和检测。脾脏和肾脏已被报道为 VHSV 感染的主要靶器官；然而，VHSV 如何在鱼体内传播尚未得到明确研究。本研究的目的是：1）在 10°C 和 13°C 时，调查感染 VHSV 的橄榄石斑鱼血液中的病毒滴度和病毒 RNA 拷贝数；2）比较通过两种不同挑战暴露于病毒的鱼的 VHSV 滴度和病毒 RNA 拷贝数。在注射挑战组的血液样本中，10°C 时的 VHSV 滴度高于 13°C。然而，在浸泡挑战组的血液样本中，在 10°C 和 13°C 时观察到相似的滴度。在 10°C 时，与注射挑战组相比，浸泡挑战组血液中 VHSV-N 基因的拷贝数略有增加。在 13°C 时，注射和浸泡挑战组之间观察到类似的模式。此外，与我们之前的研究中测试的器官相比，在鱼血液中观察到更高的滴度和拷贝数。我们的结果表明，VHSV 基因组在感染后早期存在于鱼血液中，血液可能有助于病毒在整个鱼体中的传播。此外，通过 qRT-PCR 从鱼血液样本中进行 VHSV 诊断，不需要牺牲宿主鱼，可以收集病毒感染的动力学信息，这很有价值。
