Although the Dictyocaulus lungworm, the agent of dictyocaulosis, is one of parasitological threats to European bison, its systematic position remains unclear. The aim of the present study was to evaluate the morphological features of the lungworm and the pathological lesions it induces, and to analyse mitochondrial (mt) genetic markers for systematic and molecular epidemiological studies. The morphological findings indicate that Dictyocaulus lungworms of European bison can be distinguished from those of cattle on the basis of differences in buccal capsule wall length, total body length, and spicules length in males, all of which were significantly longer in those of European bison. Nucleotide diversity calculated from pairwise sequence alignments of partial cytochrome c oxidase subunit 1 (cox1), cytochrome B (cytB) and NADH dehydrogenase subunit 5 (nad5) of specimens from cattle and European bison varied from 1.7% for nad5, 2.1% for cytB, to 3.7% for cox1 gene. Thus, among the lungworms of European bison and cattle, nad5 and cytB were the most conserved proteins, whereas cox1 was the most diverse. The mt cytB marker gene may be a suitable candidate for distinguishing between the two genotypes, as nad5 demonstrated the greatest within-genus sequence variation. The lung tissue of infected European bison manifests signs of verminous pneumonia characterized by interstitial pneumonia, bronchitis and bronchiolitis. Therefore, it appears that European bison and cattle are infected with slightly diverged, morphologically-different, genotypes of D. viviparus, indicating they belong to two separate worm populations. We propose, therefore, that the lungworm of European bison should be classified as D. viviparus subsp. bisontis.

尽管独角龙病的病原体是双歧杆菌，是欧洲野牛的寄生虫学威胁之一，但其系统地位尚不清楚。本研究的目的是评估肺炎的形态特征及其诱发的病理病变，并分析线粒体（mt）遗传标记以进行系统和分子流行病学研究。形态学发现表明，ic齿目可以根据雄性颊囊壁长度，总体长和针尖长度的差异来区分欧洲野牛的肺虫和牛，而欧洲野牛的这些虫都明显更长。从成对序列比对计算出的核苷酸多样性局部细胞色素c ^氧化酶亚基1（COX 1），细胞色素B（CYT B）和NADH脱氢酶亚单位5（NAD的从牛和欧洲野牛标本从1.7％变化5），用于NAD 5，2.1 ％为细胞色素B，以3.7％的cox 1基因。因此，在欧洲野牛和牛的肺虫中，nad 5和cytB是最保守的蛋白质，而cox 1是最多样化的蛋白质。所述MT细胞色素乙标记基因可以是用于在两个基因型之间进行区分的合适候选，作为NAD 5展示了最大内-属序列变异。被感染的欧洲野牛的肺组织表现出以间质性肺炎，支气管炎和细支气管炎为特征的肺炎的迹象。因此，看来，欧洲野牛和牛感染了轻微发散，形态，不同的基因型D.胎生，表明它们属于两个独立的虫群。因此，我们建议将欧洲野牛的lung虫归类为维氏假单胞菌亚种。Bisontis。