Gross Lynden, Richard Jon, Hershberger Paul, Garver Kyle
Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, BC V9T 6N7, Canada.
Dis Aquat Organ. 2019 Sep 5;135(3):201-209. doi: 10.3354/dao03398.
Viral hemorrhagic septicemia virus (VHSV) genotype IVa is an endemic pathogen to the marine waters of British Columbia, with numerous marine fishes being susceptible to infection and disease, including Atlantic salmon Salmo salar reared in open net-pen aquaculture. The susceptibility of Atlantic salmon and sockeye salmon Oncorhynchus nerka to VHSV-IVa infection was evaluated using exposure routes including injection, static immersion, and cohabitation with diseased Pacific herring Clupea pallasii. Exposed fish were monitored for mortality and external pathology, mortalities were tested by virus isolation assay, and live fish were regularly sampled and screened for infection. Among injected sockeye, VHSV was detected in 1 mortality (n = 195) and 2 sub-sampled fish (n = 30), whereas sockeye exposed by immersion and cohabitation did not experience mortality nor was systemic infection indicated by tissue screening. Injection and cohabitation exposure routes confirmed the susceptibility of Atlantic salmon to VHSV. Neither sockeye nor Atlantic salmon surviving the cohabitation served as a reservoir of VHSV, but Pacific herring did. The results suggest that VHSV-IVa poses low risk to sockeye salmon under natural routes of exposure.
病毒性出血性败血症病毒（VHSV）IVa基因型是不列颠哥伦比亚省海域的一种地方性病原体，许多海洋鱼类都易受其感染并患病，包括开放式网箱养殖的大西洋鲑鱼Salmo salar。使用注射、静态浸泡以及与患病太平洋鲱鱼Clupea pallasii同居等暴露途径，评估了大西洋鲑鱼和红大麻哈鱼Oncorhynchus nerka对VHSV-IVa感染的易感性。对暴露的鱼进行死亡率和外部病理学监测，通过病毒分离试验检测死亡率，定期对存活鱼进行采样并筛查感染情况。在注射的红大麻哈鱼中，在1条死亡鱼（n = 195）和2条抽样鱼（n = 30）中检测到VHSV，而通过浸泡和同居暴露的红大麻哈鱼未出现死亡，组织筛查也未显示有全身感染。注射和同居暴露途径证实了大西洋鲑鱼对VHSV的易感性。同居后存活的红大麻哈鱼和大西洋鲑鱼都不是VHSV的储存宿主，但太平洋鲱鱼是。结果表明，在自然暴露途径下，VHSV-IVa对红大麻哈鱼构成的风险较低。
