Departamento de Ciências Biológicas, Universidade Federal de São Paulo, Rua Professor Artur Riedel 275, Jardim Eldorado, Diadema, SP, Brazil.
Vet Parasitol. 2009 Oct 28;165(1-2):25-9. doi: 10.1016/j.vetpar.2009.07.001. Epub 2009 Jul 10.
In this report, we describe the morphology and histopathology of Myxobolus salminus n. sp., a parasite of the gill filaments of wild Salminus brasiliensis (dourado) from the Brazilian Pantanal. The small polysporic plasmodia were approximately 100 microm in diameter and the development was asynchronous. The mature spores were oval to pear shaped and had a smooth wall. The spore measurements were (mean+/-S.D., with range in parentheses): length 10.1+/-0.4 microm (9.6-10.5), width 6.1+/-0.4 microm (5.8-6.6) and thickness 5.0+/-0.6 microm (4.7-5.3). The polar capsules were elongated and of equal size: length 4.6+/-0.2 microm (4.3-4.8) and width 1.7+/-0.1 microm (1.5-1.9). The histological analysis revealed numerous plasmodia in the blood vessels of the gill filaments. The site of parasite development was the wall of the large-caliber blood vessel of the gill filament, with progressive growth towards the lumen, resulting in the obstruction of blood flow, congestion and perivascular edema. The ultrastructural study revealed that the plasmodial wall was composed of two membranes, had numerous pinocytic canals and was in direct contact with the basement membrane of the vessel. The development of the parasite was asynchronous, with mature spores, immature spores and young developmental stages randomly distributed throughout the plasmodium. The prevalence of the parasite was 4.4%, with male and female fish being infected.
本报告描述了寄生在巴西潘塔纳尔野生萨尔米纽斯·布拉西利恩西斯（多瓦多）鳃丝上的 Myxobolus salminus n. sp. 的形态和组织病理学特征。小多孢子质团直径约 100 微米，发育不同步。成熟孢子呈椭圆形到梨形，壁光滑。孢子测量值为（平均值+/-标准差，括号内为范围）：长 10.1+/-0.4 微米（9.6-10.5），宽 6.1+/-0.4 微米（5.8-6.6）和厚 5.0+/-0.6 微米（4.7-5.3）。极囊细长且大小相等：长 4.6+/-0.2 微米（4.3-4.8）和宽 1.7+/-0.1 微米（1.5-1.9）。组织学分析显示，鳃丝血管中有大量质团。寄生虫发育的部位是鳃丝大口径血管的壁，随着向管腔的渐进生长，导致血流阻塞、充血和血管周围水肿。超微结构研究显示，质团壁由两层膜组成，有许多胞饮小泡，并与血管的基底膜直接接触。寄生虫的发育不同步，成熟孢子、未成熟孢子和年轻发育阶段随机分布在整个质团中。寄生虫的流行率为 4.4%，雌雄鱼均被感染。
