ABSTRACT: Infectious haematopoietic necrosis virus (IHNV) is the causative agent of infectious haematopoietic necrosis (IHN), a disease of salmonids responsible for great economic losses. The disease occurs in most parts of the world where rainbow trout is reared but has not been previously reported in North Macedonia. In this study, 150 pooled samples in total, each consisting of organ mix of 10 freshly killed rainbow trout Oncorhynchus mykiss, were collected from 50 trout farms by the Food and Veterinary Agency of North Macedonia as part of the annual surveillance plan for IHN and viral haemorrhagic septicaemia (VHS) control. Screening of samples was done by cell culture and real-time RT-PCR (qRT-PCR). All 150 tested samples were VHS virus (VHSV) qRT-PCR negative. Two samples from different trout farms were IHNV qRT-PCR positive. On cell culture, 1 IHNV qRT-PCR positive sample caused cytopathic effect after 2 passages on EPC cells. The virus, isolated from an asymptomatic rainbow trout fry, was identified by qRT-PCR and designated as MAKIHNV1. The phylogenetic reconstruction indicates that the isolated virus belongs to the European E genogroup, more specifically within the E-1 clade, and is similar to the German, Italian and Iranian isolates. This study has revealed for the first time the presence of IHNV in rainbow trout in North Macedonia. However, it is not possible to make interpretations about the source of infection from the phylogenetic analysis, and the origin of MAKIHNV1 remains unclear.

中文翻译：

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在北马其顿的养殖虹鳟中首次发现传染性造血坏死病毒。

摘要：传染性造血细胞坏死病毒（IHNV）是传染性造血细胞坏死（IHN）的病原体，是造成巨大经济损失的鲑鱼类疾病。该病发生在世界上大多数地方都饲养虹鳟鱼的地区，但以前在北马其顿尚未报道过。在这项研究中，总共收集了150个样本，每个样本都包含10个新鲜杀死的虹鳟Oncorhynchus mykiss的器官混合物是北马其顿食品和兽医局从50个鳟鱼养殖场收集的，作为IHN和病毒性出血性败血病（VHS）控制年度监测计划的一部分。通过细胞培养和实时RT-PCR（qRT-PCR）进行样品筛选。所有150个测试样品均为VHS病毒（VHSV）qRT-PCR阴性。来自不同鳟鱼养殖场的两个样品均为IHNV qRT-PCR阳性。在细胞培养中，1个IHNV qRT-PCR阳性样品在EPC细胞传代2次后引起细胞病变作用。从无症状虹鳟鱼苗中分离出的病毒通过qRT-PCR鉴定，命名为MAKIHNV1。系统发育重建表明分离出的病毒属于欧洲E基因组，更确切地说属于E-1进化枝，类似于德国，意大利和伊朗的分离株。这项研究首次揭示了北马其顿虹鳟中存在IHNV。但是，不可能通过系统发育分析来解释感染的来源，并且MAKIHNV1的来源仍不清楚。