Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts, United States of America.
Department of Medical Education, Tufts University School of Medicine, Boston, Massachusetts, United States of America.
PLoS Negl Trop Dis. 2020 Apr 2;14(4):e0007951. doi: 10.1371/journal.pntd.0007951. eCollection 2020 Apr.
Schistosomes are parasitic blood flukes that infect >200 million people around the world. Free-swimming larval stages penetrate the skin, invade a blood vessel, and migrate through the heart and lungs to the vasculature of the liver, where maturation and mating occurs. From here, the parasite couples migrate to their preferred egg laying sites. Here, we compare and contrast what is known about the migration patterns within the definitive host of the three major species of human schistosome: Schistosoma mansoni, S. japonicum, and S. haematobium. We conclude that intravascular schistosomes are inexorable colonizers whose migration and egg laying strategy is profligate; all three species (and their eggs) can be found throughout the mesenteric venules, the rectal venous plexus, and, to a greater or lesser extent, the urogenital venous plexuses. In addition, it is common for parasite eggs to be deposited in locations that lack easy access to the exterior, further demonstrating the relentless exploratory nature of these intravascular worms.
血吸虫是寄生在血液中的扁形动物,感染了全球超过 2 亿人。自由游动的幼虫穿透皮肤,侵入血管,并通过心脏和肺部迁移到肝脏的脉管系统,在那里成熟并交配。从这里开始,寄生虫伴侣迁移到它们首选的产卵部位。在这里,我们比较和对比了三种主要人类血吸虫(曼氏血吸虫、日本血吸虫和埃及血吸虫)在终宿主体内的迁移模式。我们得出结论,血管内血吸虫是不可阻挡的殖民者,它们的迁移和产卵策略是挥霍无度的;所有三种物种(及其卵)都可以在肠系膜小静脉、直肠静脉丛中找到,并且在不同程度上可以在泌尿生殖静脉丛中找到。此外,寄生虫卵沉积在不易到达外部的位置是很常见的,这进一步证明了这些血管内蠕虫具有无情的探索性。