Norwegian Veterinary Institute, Oslo, Norway.
J Fish Dis. 2013 Feb;36(2):129-39. doi: 10.1111/jfd.12008. Epub 2012 Nov 6.
Cardiomyopathy syndrome (CMS) in Atlantic salmon, Salmo salar L., is a severe cardiac disease characterized by a necrotizing myocarditis involving the atrium and the spongious part of the ventricle. The disease is caused by piscine myocarditis virus (PMCV), a double-stranded RNA virus likely belonging to the family Totiviridae. The objective of this study was to evaluate the genetic variation in Norwegian PMCV isolates focusing on the putative structural proteins encoded by open reading frames (ORFs) 1 and 3. The virus isolates were sampled from a total of 36 farms along the Norwegian coastline. This study represents the first investigation of PMCV genome variation and shows that Norwegian isolates are highly similar, with the most divergent isolates sharing 98.6% nucleotide identity. Interestingly, amino acid sequence diversity within ORF3 is approximately threefold higher than for ORF1. While phylogenetic analysis based on concatenated nucleotide data covering ORF1 and ORF3 revealed four main clusters, the maximum sequence variation of 1.4% at the nucleotide level suggests that all Norwegian isolates belong to a single genogroup. Substantial sequence variation within farms was also observed, which may complicate future molecular epidemiological investigations. The genetic homogeneity among the Norwegian isolates might facilitate development of both diagnostic tools and an efficient vaccine against CMS in the future.
大西洋鲑鱼心肌病综合征（CMS）是一种严重的心脏病，其特征为涉及心房和心室海绵部分的坏死性心肌炎。该病由鱼类心肌炎病毒（PMCV）引起，PMCV 是一种双链 RNA 病毒，可能属于 Totiviridae 科。本研究旨在评估挪威 PMCV 分离株的遗传变异，重点关注开放阅读框（ORF）1 和 3 编码的假定结构蛋白。这些病毒分离株是从挪威海岸线的总共 36 个农场中采集的。本研究首次对 PMCV 基因组变异进行了调查，结果表明挪威分离株高度相似，最具差异的分离株共享 98.6%的核苷酸同一性。有趣的是，ORF3 内的氨基酸序列多样性约为 ORF1 的三倍。虽然基于涵盖 ORF1 和 ORF3 的拼接核苷酸数据的系统发育分析显示出四个主要聚类，但核苷酸水平 1.4%的最大序列变异表明所有挪威分离株均属于单个基因群。在农场内也观察到大量的序列变异，这可能使未来的分子流行病学调查复杂化。挪威分离株之间的遗传同质性可能有助于未来开发 CMS 的诊断工具和有效疫苗。
