Køie M
Marine Biological Laboratory, University of Copenhagen, Helsingør, Denmark.
Int J Parasitol. 1991 Sep;21(5):597-602. doi: 10.1016/0020-7519(91)90065-f.
Previously undescribed motile cystophorous cercariae which develop in sporocyst-like germinal sacs in the bullomorph opisthobranch Philine aperta are experimentally shown to develop into Lecithocladium excisum (Digenea, Hemiuridae), a common stomach parasite of mackerel Scomber scombrus in the north-east Atlantic and adjacent seas. Between 3 and 8% of P. aperta from the northern Oresund, Denmark, were infected with cercariae of L. excisum. Ninety per cent were infected with Rhopalura sp. (Orthonectida). Copepods of the genera Acartia, Paracalanus, Pseudocalanus, Eurytemora and Oithona were experimentally infected. Pressure exerted by their mouth limbs caused delivery tube eversion and the injection of the cercarial body into the copepod haemocoel. The metacercariae did not grow in the above mentioned hosts at 12 degrees C, but 590 microns long metacercariae developed within 22 days in laboratory-reared A. tonsa at 18 degrees C. The ctenophore Pleurobrachia pileus and the holoplanktonic polychaete Tomopteris helgolandica, which were found to be naturally infected with metacercariae of L. excisum, may act as transport hosts.
先前未被描述过的能运动的具孢囊尾蚴在裸鳃目软体动物菲氏海兔类似包蚴的生发囊中发育，实验表明这些尾蚴会发育成截形叶形吸虫（复殖目，半尾科），它是东北大西洋及邻近海域鲭鱼的常见胃寄生虫。丹麦厄勒海峡北部的菲氏海兔中有3%至8%感染了截形叶形吸虫的尾蚴。90%感染了Rhopalura sp.（直泳目）。实验感染了哲水蚤属、拟哲水蚤属、伪哲水蚤属、真宽水蚤属和小海链藻属的桡足类。它们口肢施加的压力导致输送管外翻，并将尾蚴体注入桡足类的血腔。在12摄氏度时，上述宿主中的后尾蚴不会生长，但在18摄氏度下，实验室饲养的汤氏纺锤水蚤体内的后尾蚴在22天内发育到590微米长。被发现自然感染了截形叶形吸虫后尾蚴的栉水母侧腕水母和全浮游多毛类赫氏桨毛足虫可能充当转运宿主。
