Eriksson-Kallio Anna Maria, Holopainen Riikka, Viljamaa-Dirks Satu, Vennerström Pia, Kuukka-Anttila Hanna, Koski Perttu, Gadd Tuija
Finnish Food Safety Authority Evira, Research and Laboratory Department, Production Animal and Wildlife Health Research Unit, Mustialankatu 3, 00790 Helsinki, Finland.
Dis Aquat Organ. 2016 Feb 11;118(1):21-30. doi: 10.3354/dao02951.
Infectious pancreatic necrosis (IPN) is a contagious viral disease of fish that causes economic losses in aquaculture worldwide. In Finland, IPN virus (IPNV) has been isolated since 1987 from adult fish showing no signs of clinical disease at fish farms located in the coastal areas of the Baltic Sea. The inland area of Finland, however, remained free of IPN until 2012, when fish on several rainbow trout farms were diagnosed IPNV-positive. The fish mortalities detected at the farms were low, but clinical signs and histopathological changes typical for IPNV infection were seen in juvenile salmonids. IPNV was isolated at high water temperatures up to 22°C. In 2013 and 2014, IPNV detections continued at inland farms, indicating that infections have spread. The aim of this study was to describe the epidemiology of the outbreak and to characterise the Finnish inland IPNV isolates using histopathological, immunohistochemical and genetic approaches. In order to determine the epidemiological origin of the inland IPNV infections, the partial viral capsid protein (VP2) gene sequences of the inland IPNV isolates were compared with the sequences of the isolates from the coastal farms. Based on the genetic analysis, the inland isolates belong to IPNV Genogroup 2 (Serotype A3/Ab), and the origin of the isolates appears to be one or several coastal fish farms.
传染性胰腺坏死（IPN）是一种鱼类传染性病毒病，在全球水产养殖中造成经济损失。自1987年以来，在芬兰波罗的海沿岸地区的养鱼场中，已从无临床疾病迹象的成年鱼中分离出IPN病毒（IPNV）。然而，芬兰内陆地区直到2012年一直没有IPN，当时几个虹鳟鱼养殖场的鱼被诊断为IPNV阳性。养殖场检测到的鱼死亡率很低，但在幼年鲑科鱼类中出现了IPNV感染典型的临床症状和组织病理学变化。在高达22°C的水温下分离出了IPNV。2013年和2014年，内陆养殖场持续检测到IPNV，表明感染已经传播。本研究的目的是描述疫情的流行病学特征，并使用组织病理学、免疫组织化学和遗传学方法对芬兰内陆IPNV分离株进行特征分析。为了确定内陆IPNV感染的流行病学起源，将内陆IPNV分离株的部分病毒衣壳蛋白（VP2）基因序列与沿海养殖场分离株的序列进行了比较。基于遗传分析，内陆分离株属于IPNV基因群2（血清型A3/Ab），分离株的起源似乎是一个或几个沿海养鱼场。
