Meaders Marlene D, Hendrickson Gary L
Department of Fisheries Biology, College of Natural Resources, Humboldt State University, 1 Harpst St, Arcata, California 95521, USA.
J Parasitol. 2009 Dec;95(6):1397-407. doi: 10.1645/GE-2074.1.
The life cycle from release of myxospore sporoplasm to mature actinospore for the myxozoan parasite Ceratomyxa shasta in the freshwater polychaete host is described. Infection was initiated through exposure to lab-infected waters. Mature myxospores were present in the gut of segment 4 by 2 hr post-exposure (PE). Migration of early developmental stages occurred from the gut epithelium, through the nervous system, and into the epidermis. Once the parasite reached the epidermis, development typically occurred in segments 6-10. Life stages in the epidermis included a proliferative stage (schizogony), development of a pansporocyst (gametogony), sexual reproduction (gametogamy), and spore formation (sporogony). At water temperatures averaging 17.3 C, schizogony began by 3 hr PE, gametogony by 14 days PE, gametogamy by 35 days PE, and sporogony between 35 and 49 days PE. Development of mature actinospores took approximately 49 days PE. Up to 13,650 ± 7,807 actinospores could be released from a single polychaete over a 14-day period. Actinospores appeared to be released directly through the epidermis into the water column.
描述了粘孢子虫寄生虫沙斯塔角形虫在淡水多毛类宿主中从粘孢子原生质体释放到成熟放射孢子的生命周期。通过暴露于实验室感染的水体引发感染。暴露后2小时，成熟的粘孢子出现在第4节的肠道中。早期发育阶段从肠道上皮迁移，穿过神经系统，进入表皮。一旦寄生虫到达表皮，发育通常发生在第6 - 10节。表皮中的生命阶段包括增殖阶段（裂体生殖）、泛孢子囊的发育（配子生殖）、有性生殖（配子配合）和孢子形成（孢子生殖）。在平均水温17.3℃时，裂体生殖在暴露后3小时开始，配子生殖在暴露后14天开始，配子配合在暴露后35天开始，孢子生殖在暴露后35至49天之间开始。成熟放射孢子的发育大约需要暴露后49天。在14天的时间里，单个多毛类动物最多可释放13,650 ± 7,807个放射孢子。放射孢子似乎直接通过表皮释放到水柱中。
