Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, China.
Hubei Engineering Technology Research Center for Aquatic Animal Diseases Control and Prevention, Wuhan, China.
J Fish Dis. 2020 Oct;43(10):1177-1184. doi: 10.1111/jfd.13178. Epub 2020 Aug 1.
Myxozoans usually have a complex life cycle involving indirect transmission between vertebrate and invertebrate hosts. The vertical transmission of these parasites in vertebrate hosts has not been documented so far. Here, we assessed whether the myxozoan parasite Myxobolus honghuensis is vertically transmitted in naturally infected allogynogenetic gibel carp Carassius auratus gibelio (Bloch). M. honghuensis infection of broodfish, fertilized eggs and laboratory-cultured progeny was monitored in 2018 and 2019. The presporogonic stage was microscopically observed in the pharynx of broodfish and their progeny. In situ hybridization confirmed the presence of M. honghuensis presporogonic stage in the pharynx of broodfish and progeny. Nested PCR results showed that M. honghuensis was present in tissues and eggs of broodfish, fertilized eggs and their corresponding progeny. The sequences obtained from broodfish and progeny showed 98.0-99.8% similarity with ITS-5.8S rDNA of M. honghuensis. This study provides molecular and light microscopy evidence for the transfer of M. honghuensis from broodfish to progeny via the eggs, but it is insufficient to assert that M. honghuensis can transmit vertically in naturally infected allogynogenetic gibel carp. This is the first record about vertical transfer of myxozoan in the vertebrate host.
粘孢子虫通常具有复杂的生活史，涉及脊椎动物和无脊椎动物宿主之间的间接传播。这些寄生虫在脊椎动物宿主中的垂直传播迄今尚未记录。在这里，我们评估了粘孢子虫寄生虫 Myxobolus honghuensis 是否在自然感染的异育银鲫 Carassius auratus gibelio（Bloch）中垂直传播。在 2018 年和 2019 年监测了亲鱼、受精卵和实验室培养后代中 M. honghuensis 的感染情况。在亲鱼及其后代的咽部观察到前孢子虫阶段的显微镜观察。原位杂交证实了亲鱼和后代咽部存在 M. honghuensis 前孢子虫阶段。巢式 PCR 结果显示 M. honghuensis 存在于亲鱼、受精卵及其相应后代的组织和卵中。从亲鱼和后代获得的序列与 M. honghuensis 的 ITS-5.8S rDNA 显示出 98.0-99.8%的相似性。本研究为 M. honghuensis 通过卵从亲鱼转移到后代提供了分子和光学显微镜证据，但不足以断言 M. honghuensis 可以在自然感染的异育银鲫中垂直传播。这是关于脊椎动物宿主中粘孢子虫垂直转移的第一个记录。
