Appy Ralph G, Butterworth Eric W
Cabrillo Marine Aquarium, 3720 Stephen M. White Drive, San Pedro, California 90731, USA.
J Parasitol. 2011 Dec;97(6):1035-48. doi: 10.1645/GE-2878.1. Epub 2011 Jul 14.
Experimentally transmitted Ascarophis sp. (Spirurida) developed to adult worms in the invertebrate host, Gammarus deubeni (Amphipoda), collected in the intertidal zone in Passamaquoddy Bay, New Brunswick, Canada. The morphological development and growth of larval stages is very similar to other cystidicolids, which are found as adults in fish. Unlike virtually all other Spirurida, which require a vertebrate definitive host, infective larvae of Ascarophis sp. migrate from the invertebrate host musculature into the hemocoel where they molt twice to become adults. Gravid females appear at 80 days and 69 days post-infection at 10-12 C and 18-20 C, respectively. While there is little evident host reaction to the parasite within the muscle tissue, within the hemocoel there is hemocytic reaction to shed nematode cuticles, released eggs, and sometimes the worm itself, including some melanization. The worms are morphologically similar to Ascarophis sp. from G. oceanicus in the Baltic and White seas and among Ascarophis species from fish is most similar to A. arctica. It is suggested that Ascarophis sp. no longer requires a vertebrate host and is transmitted between amphipods either through death and disintegration of infected amphipods and dispersal of the nematode eggs, or more likely through cannibalism or necrophagy.
通过实验传播的蛔虫属（旋尾目）在无脊椎动物宿主——加拿大新不伦瑞克省帕萨马夸迪湾潮间带采集的杜氏钩虾（双甲目）体内发育为成虫。幼虫阶段的形态发育和生长与其他囊尾科动物非常相似，这些动物在鱼类体内为成虫。与几乎所有其他需要脊椎动物终末宿主的旋尾目动物不同，蛔虫属的感染性幼虫从无脊椎动物宿主的肌肉组织迁移到血腔，在那里它们蜕皮两次成为成虫。在10 - 12摄氏度和18 - 20摄氏度下，感染后80天和69天分别出现怀孕雌虫。虽然在肌肉组织内宿主对寄生虫几乎没有明显反应，但在血腔内，对脱落的线虫角质层、释放的卵以及有时对线虫本身会有血细胞反应，包括一些黑化现象。这些蠕虫在形态上与波罗的海和白海的大洋钩虾体内的蛔虫属相似，在鱼类的蛔虫属物种中与北极蛔虫最为相似。有人认为，蛔虫属不再需要脊椎动物宿主，而是通过受感染的钩虾死亡和分解以及线虫卵的扩散，或者更有可能通过同类相食或食尸行为在钩虾之间传播。
