Höglund J, Wilhelmsson E, Christensson D, Mörner T, Waller P, Mattsson J G
Department of Parasitology, National Veterinary Institute and Swedish University of Agricultural Sciences, Uppsala.
Int J Parasitol. 1999 Apr;29(4):607-11. doi: 10.1016/s0020-7519(98)00229-x.
Total DNA was isolated from adult lungworms of the genus Dictyocaulus, collected from cattle, moose (Alces alces) and roe deer (Capreolus capreolus) in Sweden. The second ribosomal internal transcribed spacer was amplified with PCR, and DNA sequences were determined from nine individual worms that all came from different hosts in order to avoid analysis of siblings. The sequence data obtained were aligned and compared with similar data derived from German lungworm isolates from cattle and fallow deer (Cervus dama). These analyses clearly showed that specimens of the cattle lungworm, Dictyocaulus viviparus, were almost identical irrespective of their geographical origin. However, when the second internal transcribed spacer sequence of D. viviparus was compared with that of lungworms from moose and roe deer, major differences were noticed. Although lungworms collected from these cervids had identical second internal transcribed spacer sequences, they proved to be genetically different from Dictyocaulus eckerti of German fallow deer, displaying a 66.5% similarity. In an evolutionary tree, inferred by maximum likelihood analysis, the Dictyocaulus species from cattle and wild cervids clustered as compared with Dictyocaulus filaria from sheep. The study has thus demonstrated that A. alces and C. capreolus in Sweden are parasitised with a Dictyocaulus species that is different from D. viviparus and D. eckerti, indicating that we are dealing with a new species in moose and roe deer.
从瑞典的牛、驼鹿（Alces alces）和狍（Capreolus capreolus）体内采集的网尾线虫属成年肺线虫中分离出总DNA。用聚合酶链反应（PCR）扩增第二核糖体内部转录间隔区，并从九条均来自不同宿主的个体线虫中测定DNA序列，以避免对同胞线虫进行分析。将获得的序列数据进行比对，并与来自德国牛和黇鹿（Cervus dama）肺线虫分离株的类似数据进行比较。这些分析清楚地表明，牛肺线虫（Dictyocaulus viviparus）的样本几乎完全相同，无论其地理来源如何。然而，当将D. viviparus的第二内部转录间隔区序列与来自驼鹿和狍的肺线虫序列进行比较时，发现了主要差异。尽管从这些鹿科动物采集的肺线虫具有相同的第二内部转录间隔区序列，但它们在基因上与德国黇鹿的埃氏网尾线虫（Dictyocaulus eckerti）不同，相似度为66.5%。在通过最大似然分析推断出的进化树中，来自牛和野生鹿科动物的网尾线虫物种与来自绵羊的丝状网尾线虫（Dictyocaulus filaria）聚类。因此，该研究表明，瑞典的驼鹿和狍感染了一种与D. viviparus和D. eckerti不同的网尾线虫物种，这表明我们正在处理一种存在于驼鹿和狍体内的新物种。
