Sréter-Lancz Z, Széll Z, Sréter T
Laboratories for Food Microbiology, Food and Feed Safety Directorate, Central Agricultural Office, 1091 Budapest, Mester u. 81, Hungary.
Vet Parasitol. 2007 Sep 30;148(3-4):365-70. doi: 10.1016/j.vetpar.2007.06.021. Epub 2007 Jul 27.
In the past 15 years, subconjunctival onchocercosis has been reported from 63 dogs in south-western United States (Arizona, California, Utah) and Southern and Central Europe (Germany, Greece, Hungary, Portugal, Switzerland). To reveal the taxonomic status of the parasite responsible for these infections, fragments of the mitochondrial cytochrome oxidase subunit I (COI) and NADH dehydrogenase subunit 5 (ND5) genes of three European strains of canine Onchocerca sp. and the 16S ribosomal RNA (16S rRNA) gene of their Wolbachia endosymbionts were sequenced and compared to the homologous sequences of other spirurid nematodes. The evolutionary divergence between COI and ND5 gene sequences of Greek, Hungarian and Portuguese strains of canine Onchocerca sp. were similar in magnitude to that seen within Thelazia callipaeda or Onchocerca lienalis. The evolutionary divergence between the sequences of canine Onchocerca sp. and other Onchocerca spp. including O. lienalis were similar or higher in magnitude to that seen between other Onchocerca spp. The results of the current and earlier phylogenetic analyses indicate that canine Onchocerca sp. separated from other Onchocerca spp. early in the evolution. Based on the similar clinical pictures, the identical morphology of nematodes and the sequence analyses of COI and ND5 genes of the worms and 16S rRNA gene of their wolbachiae, the Onchocerca worms isolated from European dogs appear to belong to the same species. The results support the earlier biological and morphological arguments that a distinct species, most likely O. lupi originally described from the subconjunctival tissues of a Caucasian wolf is responsible for canine ocular onchocercosis in Europe.
在过去15年中，美国西南部（亚利桑那州、加利福尼亚州、犹他州）以及南欧和中欧（德国、希腊、匈牙利、葡萄牙、瑞士）有63只犬被报道患有结膜下盘尾丝虫病。为了揭示引发这些感染的寄生虫的分类地位，对三株欧洲犬盘尾丝虫属线虫的线粒体细胞色素氧化酶亚基I（COI）和NADH脱氢酶亚基5（ND5）基因片段以及它们的沃尔巴克氏体共生菌的16S核糖体RNA（16S rRNA）基因进行了测序，并与其他旋尾目线虫的同源序列进行了比较。希腊、匈牙利和葡萄牙犬盘尾丝虫属线虫的COI和ND5基因序列之间的进化分歧程度与结膜吸吮线虫或链尾盘尾丝虫内部的情况相似。犬盘尾丝虫属线虫与包括链尾盘尾丝虫在内的其他盘尾丝虫属线虫序列之间的进化分歧程度与其他盘尾丝虫属线虫之间的情况相似或更高。当前和早期系统发育分析的结果表明，犬盘尾丝虫属线虫在进化早期就与其他盘尾丝虫属线虫分离开来。基于相似的临床表现、线虫相同的形态以及线虫的COI和ND5基因以及它们沃尔巴克氏体的16S rRNA基因的序列分析，从欧洲犬分离出的盘尾丝虫似乎属于同一物种。这些结果支持了早期的生物学和形态学观点，即一种独特的物种，很可能是最初从一只高加索狼的结膜下组织中描述的狼盘尾丝虫，是欧洲犬眼盘尾丝虫病的病原体。
