Viral haemorrhagic septicaemia virus (VHSV) is a negative‐sense single‐stranded RNA virus that infects more than 140 different fish species. In this study, zebrafish larvae were employed as in vivo model organisms to investigate progression of disease, the correlation between propagation of the infection and irreversibility of disease, cell tropism and in situ neutrophil activity towards the VHSV‐infected cells. A recombinant VHSV strain, encoding “tomato” fluorescence (rVHSV‐Tomato), was used in zebrafish to be able to follow the progress of the infection in the live host in real‐time. Two‐day‐old zebrafish larvae were injected into the yolk sac with the recombinant virus. The virus titre peaked 96 hr post‐infection in zebrafish larvae kept at 18°C, and correlated with 33% mortality and high morbidity among the larvae. By utilizing the transgenic zebrafish line Tg(fli1:GFP)^y1 with fluorescently tagged endothelial cells, we were able to demonstrate that the virus initially infected endothelial cells lining the blood vessels. By observing the rVHSV‐Tomato infection in the neutrophil reporter zebrafish line Tg(MPX:eGFP)ⁱ¹¹⁴, we inferred that only a subpopulation of the neutrophils responded to the virus infection. We conclude that the zebrafish larvae are suitable for real‐time studies of VHS virus infections, allowing in vivo dissection of host–virus interactions at the whole organism level.

中文翻译：

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斑马鱼（Danio rerio）幼虫作为传播VHS病毒感染，组织嗜性和嗜中性粒细胞活性的实时研究模型

病毒性败血症病毒（VHSV）是一种负义单链RNA病毒，感染了140多种不同的鱼类。在这项研究中，斑马鱼幼虫被用作体内模型生物来研究疾病的进展，感染的传播与疾病的不可逆性之间的相关性，细胞嗜性和原位中性粒细胞对VHSV感染细胞的活性。在斑马鱼中使用了编码“番茄”荧光的重组VHSV株（rVHSV-Tomato），以便能够实时跟踪活宿主中感染的进程。将两天大的斑马鱼幼虫与重组病毒一起注入卵黄囊。在温度保持在18°C的斑马鱼幼虫中，病毒滴度在感染后96小时达到峰值，并与33％的死亡率和幼虫中的高发病率相关。通过利用带有荧光标记的内皮细胞的转基因斑马鱼品系Tg（fli1：GFP）^y1，我们能够证明该病毒最初感染了位于血管内的内皮细胞。通过观察嗜中性粒细胞报道者斑马鱼系Tg（MPX：eGFP）^i114中的rVHSV-Tomato感染，我们推断只有一部分嗜中性粒细胞对病毒感染有反应。我们得出的结论是，斑马鱼幼虫适用于VHS病毒感染的实时研究，可以在整个生物体水平上对宿主与病毒之间的相互作用进行体内解剖。