Müller V, Kimmig P
Fachgebiet Parasitologie (Institut für Zoologie), Universität Hohenheim, Germany.
Appl Parasitol. 1994 Feb;35(1):12-31.
Ocellate furcocercariae from the lymnaeid snail Radix auricularia have been identified as causative agents of swimmer's itch, which has become increasingly common in the 'Tunisee' near Freiburg. On an average 11.0%, maximally 25.0%, of the snails were parasitized with these trematode larvae. The Trichobilharzia parasitizing rate in the intermediate hosts found here was thus approximately 10-100 times higher than the Trichobilharzia prevalence described so far. Dwarf mallards (Anas platyrhynchos, blood red) were experimentally infected with Trichobilharzia cercariae from the 'Tunisee'. From the 13th day p.i. miracidia could be found in their faeces by means of the hatching method. The trematode eggs had the shape of an elongated spindle, with a pointed and a rounded end. The sexually differentiated adult worms were localized only in the hepatic and enteric veins. They had an average length of 4.0 mm (3.2-4.6 mm) and a width of 125 microns. Their tegument was strongly folded and had tegumental spines in the oral and ventral suckers, in males in addition along the canalis gynaecophorus. The most striking internal organ was the gut filled with hematin and separated in 2 caeca at its anterior end. Its form and localisation as well as those of the sexual organs were important criteria for the differentiation of the different Trichobilharzia species. The Trichobilharzia species found in the 'Tunisee' clearly differed from Trichobilharzia szidati both morphologically and physiologically. The latter has been considered, until now, to be the main causative agent of swimmer's itch in Germany. Moreover, the adult trematodes from the 'Tunisee' could not be associated with any other species of this genus. We propose therefore the name Trichobilharzia franki n. sp. for the species from the Tunisee.
已确认耳萝卜螺（Radix auricularia）体内的眼点叉尾尾蚴是游泳者皮疹的病原体，这种疾病在弗赖堡附近的“图尼湖”（Tunisee）愈发常见。平均有11.0%的螺蛳被这些吸虫幼虫寄生，最高可达25.0%。因此，这里发现的中间宿主中毛毕吸虫的寄生率比迄今所描述的毛毕吸虫感染率高出约10至100倍。将矮脚野鸭（绿头鸭，血红亚种，Anas platyrhynchos, blood red）用来自“图尼湖”的毛毕吸虫尾蚴进行实验性感染。感染后第13天起，通过孵化法可在其粪便中发现毛蚴。吸虫卵呈细长纺锤形，一端尖一端圆。雌雄异体的成虫仅寄生于肝静脉和肠静脉。它们平均体长4.0毫米（3.2 - 4.6毫米），宽125微米。其体表有强烈褶皱，在口吸盘和腹吸盘中有体表棘，雄性在抱雌沟沿线也有。最显著的内部器官是充满血色素的肠道，前端分为两个盲囊。其形态、位置以及性器官的形态和位置是区分不同毛毕吸虫种类的重要标准。在“图尼湖”发现的毛毕吸虫种类在形态和生理上与斯氏毛毕吸虫（Trichobilharzia szidati）明显不同。直到现在，后者一直被认为是德国游泳者皮疹的主要病原体。此外，来自“图尼湖”的成年吸虫无法与该属的任何其他种类相关联。因此，我们提议将来自“图尼湖”的这个种类命名为弗氏毛毕吸虫（Trichobilharzia franki n. sp.）。
