Rimmer A E, Whittington R J, Tweedie A, Becker J A
Faculty of Veterinary Science, School of Life and Environmental Sciences, The University of Sydney, Camden, NSW, Australia.
J Fish Dis. 2017 Mar;40(3):293-310. doi: 10.1111/jfd.12510. Epub 2016 Jun 23.
Megalocytiviruses cause high mortality diseases that have seriously impacted aquaculture, with the most frequent outbreaks occurring in East and South-East Asia. The international trade of juvenile fish for food and ornamental aquaculture has aided the spread of these viruses, which have spread to Europe and Australia and other regions. Australian freshwater fishes were examined for susceptibility to infection with the exotic megalocytivirus, dwarf gourami iridovirus (DGIV), which belongs to a group with the type species, Infectious spleen and kidney necrosis virus (ISKNV). Fish were held at 23 ± 1 °C and challenged by intraperitoneal (IP) injection or by cohabitation with Murray cod, Maccullochella peelii (Mitchell) infected with DGIV. A species was deemed to be susceptible to DGIV based on evidence of viral replication, as determined by qPCR, and megalocytic inclusion bodies observed histologically. Horizontal transmission occurred between infected Murray cod and golden perch, Macquaria ambigua (Richardson), Macquarie perch, Macquaria australasica (Cuvier) and Murray cod. This indicated that DGIV shed from infected fish held at 23 °C can survive in fresh water and subsequently infect these naïve fish. Further, DGIV administered IP was highly pathogenic to golden perch, Macquarie perch and Murray cod. Compared to these species, the susceptibility of southern pygmy perch, Nannoperca australis (Gunther) was lower. Freshwater catfish (dewfish), Tandanus tandanus (Mitchell), were not susceptible under the experimental conditions based on the absence of clinical disease, mortality and virus replication. This study showed the potential risks associated with naïve and DGIV-infected fish sharing a common water source.
巨细胞病毒会引发高死亡率疾病，已对水产养殖业造成严重影响，其中最频繁的疫情爆发发生在东亚和东南亚地区。用于食用和观赏水产养殖的幼鱼国际贸易助长了这些病毒的传播，它们已传播到欧洲、澳大利亚及其他地区。对澳大利亚淡水鱼进行了检测，以确定其对感染外来巨细胞病毒——侏儒 Gourami 虹彩病毒（DGIV）的易感性，该病毒与模式种传染性脾肾坏死病毒（ISKNV）属于同一类群。将鱼饲养在 23 ± 1°C 的环境中，并通过腹腔注射或与感染 DGIV 的墨累鳕鱼（Maccullochella peelii (Mitchell)）共同饲养进行攻毒。根据 qPCR 测定的病毒复制证据以及组织学观察到的巨细胞包涵体，判定一个物种对 DGIV 易感。水平传播发生在感染的墨累鳕鱼与黄金鲈（Macquaria ambigua (Richardson)）、麦夸里鲈（Macquaria australasica (Cuvier)）和墨累鳕鱼之间。这表明在 23°C 下饲养的感染鱼排出的 DGIV 可在淡水中存活，并随后感染这些未感染的鱼。此外，腹腔注射 DGIV 对黄金鲈、麦夸里鲈和墨累鳕鱼具有高度致病性。与这些物种相比，南方侏儒鲈（Nannoperca australis (Gunther)）的易感性较低。在实验条件下，基于无临床疾病、死亡率和病毒复制情况，淡水鲶鱼（须鲶鱼，Tandanus tandanus (Mitchell)）不易感。本研究显示了未感染和感染 DGIV 的鱼共享共同水源所带来的潜在风险。
