Department of Veterinary Science, University of Pisa, Viale delle Piagge 2, 56124 Pisa, Italy.
Vet Parasitol. 2013 Oct 18;197(1-2):364-9. doi: 10.1016/j.vetpar.2013.06.022. Epub 2013 Jul 4.
Several species of Trichuridae nematodes can infect dogs, cats and wild mammals. The diagnosis of these infections relies on the microscopic identification of eggs which are characterized by a similar "lemon" shape and polar plugs in all Trichuridae. Thus, morphological diagnosis to species level is challenging. The use of biomolecular diagnostic methods is desirable but very little genetic data are known from Trichuridae of carnivores and small mammals. The aim of this work was to genetically characterize several species of Trichuridae that can affect dogs, cats and wild mammals, as a basis to develop molecular diagnostic tests. Specimens (adult worms or eggs) of Eucoleus aerophilus (syn. Capillaria aerophila), Eucoleus boehmi (syn. Capillaria boehmi), Pearsonema plica (syn. Capillaria plica), Aonchotheca putorii (syn. Capillaria putorii), Calodium hepaticum (syn. Capillaria hepatica), Calodium splenaecum (syn. Capillaria splenaeca) and Trichuris vulpis were obtained from carcasses of red foxes, feces of dogs, the liver of a vole and from the spleen of Crocidura sp. Parts of the small subunit rRNA (18S rRNA) gene and of the mitochondrial cytochrome c oxidase subunit I (cox 1 mtDNA) gene were amplified from the above mentioned nematodes, yielding the first 18S rRNA gene sequences of all the capillariid nematodes and the first cox 1 mtDNA sequences of E. boehmi, P. plica, C. hepaticum, A. putorii and T. vulpis. The 18S rRNA gene is highly conserved among the different species and not suitable as a target for specific diagnostic oligonucleotides. However, these sequences contribute to a better understanding of the complex taxonomic relations among Trichuridae. Indeed, a dendrogram based on the 18S rRNA gene locus supports the latest taxonomic revision. Interspecies divergence was much higher at the cox 1 mtDNA gene locus, rendering it suitable for DNA barcoding and particularly valuable in resolving closely related species. Furthermore, the mitochondrial genetic markers defined in the present study are useful to develop Trichuridae species-specific primers.
几种旋毛线虫可以感染狗、猫和野生哺乳动物。这些感染的诊断依赖于卵的显微镜鉴定，所有旋毛线虫的卵都具有相似的“柠檬”形状和极帽。因此，形态学诊断到种水平是具有挑战性的。使用生物分子诊断方法是可取的，但从食肉动物和小型哺乳动物的旋毛线虫中获得的遗传数据非常少。本工作的目的是对几种可能影响狗、猫和野生哺乳动物的旋毛线虫进行遗传特征分析，为开发分子诊断试验奠定基础。从赤狐尸体中获得了嗜肺旋毛线虫（原称 Capillaria aerophila）、波氏旋毛线虫（原称 Capillaria boehmi）、皮尔森旋毛线虫（原称 Capillaria plica）、粗腔旋毛线虫（原称 Capillaria putorii）、肝毛细线虫（原称 Capillaria hepatica）、脾毛细线虫（原称 Capillaria splenaeca）和犬钩虫的成虫和虫卵，从狗的粪便中、田鼠的肝脏中和 Crocidura sp.的脾脏中获得了。从小亚基核糖体 RNA (18S rRNA) 基因和线粒体细胞色素 c 氧化酶亚基 I (cox 1 mtDNA) 基因扩增了上述线虫的部分序列，获得了所有毛细线虫的第一个 18S rRNA 基因序列和波氏旋毛线虫、皮尔森旋毛线虫、肝毛细线虫、粗腔旋毛线虫和犬钩虫的第一个 cox 1 mtDNA 序列。18S rRNA 基因在不同物种之间高度保守，不适合作为特异性诊断寡核苷酸的靶标。然而，这些序列有助于更好地理解旋毛线虫科之间复杂的分类关系。事实上，基于 18S rRNA 基因座的系统发育树支持最新的分类修订。cox 1 mtDNA 基因座的种间差异要大得多，适合 DNA 条形码，特别是在解决密切相关的物种方面非常有价值。此外，本研究中定义的线粒体遗传标记可用于开发旋毛线虫科特异性引物。
