Glenney Gavin W, Barbash Patricia A, Coll John A, Quartz William M
U.S. Fish and Wildlife Service, Lamar Fish Health Center, 400 Washington Avenue, Lamar, Pennsylvania 16848, USA.
J Aquat Anim Health. 2012 Jun;24(2):63-72. doi: 10.1080/08997659.2012.668509.
After 22 years of negative viral screening results, the viral pathogen infectious pancreatic necrosis virus (IPNV) was isolated from the ovarian fluid of two pooled samples of returning Connecticut River Atlantic salmon Salmo salar during the 2007 spawning season at Richard Cronin National Salmon Station (RCNSS), Hadley, Massachusetts. Cytopathic effect was observed in Chinook salmon embryo (CHSE-214) cells, and IPNV was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR). Sequence analysis conducted by the U.S. Geological Survey's Western Fisheries Research Center determined that the isolate closely resembled the Canada_3 strain, falling into Genogroup 4 rather than Genogroup 1, which is more common in the United States. This allowed us to speculate that the Atlantic salmon were not infected during their freshwater life stage in the Connecticut River watershed but somewhere on their migratory route or feeding grounds in the Northwest Atlantic. On November 20, 2007, the Connecticut River Atlantic Salmon Commission voted to depopulate the infected stock at RCNSS and the entire suspect egg lots held at White River National Fish Hatchery, Vermont. Approximately one and a half months later, the 121 Connecticut River Atlantic salmon were euthanized and sampled for a follow-up investigation to determine the prevalence of infection. Only one kidney-spleen homogenate (male) was confirmed IPNV positive via cell culture and RT-PCR. A total of 2,983 base pairs from segment A of the RNA genome were sequenced from this fish and determined to be from a new strain (Connecticut-1) of IPNV that closely resembles Canada_2 and Canada_3 in Genogroup 4. The new strain is genetically identical to one of the first ovarian fluid isolates over a shared 130-nucleotide region, possibly indicating original transmission from a single source. The absence of IPNV from the Connecticut River's subsequent four returning Atlantic salmon year-classes may indicate that the aggressive corrective action was prudent.
在连续22年病毒筛查结果呈阴性之后，2007年产卵季期间，在马萨诸塞州哈德利的理查德·克罗宁国家鲑鱼站（RCNSS），从两条返回康涅狄格河的大西洋鲑鱼（Salmo salar）混合样本的卵巢液中分离出了病毒病原体传染性胰腺坏死病毒（IPNV）。在奇努克鲑胚胎（CHSE - 214）细胞中观察到细胞病变效应，并通过逆转录聚合酶链反应（RT - PCR）确认了IPNV。美国地质调查局西部渔业研究中心进行的序列分析确定，分离株与加拿大_3株非常相似，属于基因组群4，而非在美国更为常见的基因组群1。这使我们推测，大西洋鲑鱼在康涅狄格河流域的淡水生活阶段未受感染，而是在其西北大西洋的洄游路线或觅食地的某个地方受到了感染。2007年11月20日，康涅狄格河大西洋鲑鱼委员会投票决定清空RCNSS的受感染种群以及佛蒙特州白河国家鱼类孵化场保存的所有可疑鱼卵批次。大约一个半月后，对121条康涅狄格河大西洋鲑鱼实施安乐死并取样进行后续调查，以确定感染率。通过细胞培养和RT - PCR，仅一份肾脾匀浆（雄性）被确认为IPNV阳性。从这条鱼的RNA基因组A片段中总共测序了2983个碱基对，确定其来自IPNV的一个新菌株（康涅狄格 - 1），该菌株在基因组群4中与加拿大_2和加拿大_3非常相似。这个新菌株在一个共享的130个核苷酸区域与最早的一份卵巢液分离株之一基因相同，这可能表明其最初来自单一来源。在随后的四个返回康涅狄格河的大西洋鲑鱼年份群体中未检测到IPNV，这可能表明积极的纠正措施是明智之举。
