Clegg S R, Mansfield K G, Newbrook K, Sullivan L E, Blowey R W, Carter S D, Evans N J
Department of Infection Biology, Institute of Infection and Global Health, School of Veterinary Science, University of Liverpool, Liverpool, United Kingdom
Washington Department of Fish and Wildlife, Spokane Valley, Washington, USA.
J Clin Microbiol. 2015 Jan;53(1):88-94. doi: 10.1128/JCM.02276-14. Epub 2014 Oct 29.
Since 2008, a large increase in the numbers of cases of lameness have been seen in wild North American elk (Cervus elaphus) from Washington State, USA. The most recent cases manifested as foot lesions similar both clinically and pathologically to those seen in digital dermatitis (DD) in cattle and sheep, a disease with a bacterial etiopathogenesis. To determine whether the same bacteria considered responsible for DD are associated with elk lameness, lesion samples were subjected to bacterial isolation studies and PCR assays for three phylogroups of relevant DD treponemes. The DD treponemes were isolated from lesional tissues but not from control feet or other areas of the diseased foot (including the coronary band or interdigital space), suggesting that the bacteria are strongly associated with DD lesions and may therefore be causal. In addition, PCR analysis revealed that all three unique DD treponeme phylotypes were found in elk hoof disease, and in 23% of samples, all 3 DD-associated treponemes were present in lesions. Sequence analysis of the 16S rRNA gene showed that the elk lesion treponemes were phylogenetically almost identical to those isolated from cattle and sheep DD lesions. The isolates were particularly similar to two of the three culturable DD treponeme phylotypes: specifically, the Treponema medium/Treponema vincentii-like and Treponema phagedenis-like DD spirochetes. The third treponeme culturable phylogroup (Treponema pedis), although detected by PCR, was not isolated. This is the first report describing isolation of DD treponemes from a wildlife host, suggesting that the disease may be evolving to include a wider spectrum of cloven-hoofed animals.
自2008年以来，在美国华盛顿州的野生北美马鹿（Cervus elaphus）中，跛足病例数量大幅增加。最近的病例在临床和病理上均表现为足部病变，与牛羊的指皮炎（DD）相似，这是一种由细菌引起的疾病。为了确定与DD相关的相同细菌是否与马鹿跛足有关，对病变样本进行了细菌分离研究，并针对相关DD密螺旋体的三个菌系进行了PCR检测。从病变组织中分离出了DD密螺旋体，但在对照足部或患病足部的其他区域（包括冠状带或指间间隙）未分离到，这表明这些细菌与DD病变密切相关，因此可能是病因。此外，PCR分析显示，在马鹿蹄病中发现了所有三种独特的DD密螺旋体菌型，并且在23%的样本中，病变中存在所有3种与DD相关的密螺旋体。16S rRNA基因的序列分析表明，马鹿病变中的密螺旋体在系统发育上与从牛羊DD病变中分离出的密螺旋体几乎相同。分离株与三种可培养的DD密螺旋体菌型中的两种特别相似：具体来说，是中间密螺旋体/文森特密螺旋体样和蚀疮性密螺旋体样DD螺旋体。尽管通过PCR检测到了第三种可培养的密螺旋体菌系（足部密螺旋体），但未分离出来。这是第一份描述从野生动物宿主中分离出DD密螺旋体的报告，表明该疾病可能正在演变，以包括更广泛的偶蹄动物。
