Onaca F M T, da Graça R J, Fabrin T M C, Takemoto R M, de Oliveira A V
Curso de Ciências Biológicas, Universidade Estadual de Maringá - UEM, Maringá, Paraná, Brazil.
Departamento de Biologia, Universidade Estadual de Maringá - UEM, Maringá, Paraná, Brazil.
J Helminthol. 2019 Aug 15;94:e73. doi: 10.1017/S0022149X19000725.
Digeneans (Trematoda: Digenea) are endoparasites that present a complex life cycle, generally involving an intermediate invertebrate host and a vertebrate host. There is limited information about which species of molluscs may act as intermediate hosts in the upper Paraná River floodplain (UPRF), where Aylacostoma chloroticum can be considered a potential candidate. The study of digeneans in this region is important because some of these parasites are potentially zoonotic, and, therefore, are relevant to public health. However, the correct identification of these organisms during the larval stages is difficult because of the lack of morphologically diagnostic characteristics. The objective of this study was to identify and molecularly characterize the larval stages of digeneans found in A. chloroticum in the UPRF, using the mitochondrial marker of subunit I of cytochrome c oxidase and the 28S nuclear marker. The molluscs were examined in the laboratory and three morphotypes of cercariae were found. DNA was extracted from the specimens obtained and was then amplified and sequenced. The morphotypes exhibited high genetic similarities with Pseudosellacotyla, Paralecithodendrium and Philophthalmus, indicating that these organisms belong to these genera. This is the first record of larval stages of these genera in molluscs collected in the UPRF.
复殖吸虫（吸虫纲：复殖目）是体内寄生虫，具有复杂的生命周期，通常涉及一个中间无脊椎动物宿主和一个脊椎动物宿主。关于哪些软体动物物种可能在上巴拉那河泛滥平原（UPRF）充当中间宿主的信息有限，在该地区，绿点艾氏螺可被视为一个潜在候选者。对该地区复殖吸虫的研究很重要，因为其中一些寄生虫具有潜在的人畜共患性，因此与公共卫生相关。然而，由于缺乏形态学诊断特征，在幼虫阶段正确识别这些生物很困难。本研究的目的是利用细胞色素c氧化酶亚基I的线粒体标记和28S核标记，对上巴拉那河泛滥平原绿点艾氏螺中发现的复殖吸虫幼虫阶段进行鉴定和分子特征分析。在实验室对软体动物进行了检查，发现了三种尾蚴形态型。从获得的标本中提取DNA，然后进行扩增和测序。这些形态型与假塞拉科蒂拉属、副卵黄树属和嗜眼属表现出高度的遗传相似性，表明这些生物属于这些属。这是在上巴拉那河泛滥平原采集的软体动物中首次记录到这些属的幼虫阶段。
