Microbiology and Pathogenesis Activity, Bacterial Diseases Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado 80521, USA.
Vector Borne Zoonotic Dis. 2012 Nov;12(11):1000-3. doi: 10.1089/vbz.2011.0922. Epub 2012 May 31.
The enzootic cycle of Borrelia burgdorferi, the etiologic agent of Lyme disease, involves Ixodes spp. ticks and vertebrates. Resident tick Borrelia, harbored inside the midgut, are eventually expelled with the tick's saliva into the vertebrate host when a tick consumes a blood meal. During this 4- to 5-day feeding period I. scapularis will defecate onto the host's skin. Previously we detected borrelial DNA in tick feces throughout engorgement. In this study we report the microscopic examination for B. burgdorferi in nymphal excrement. Using immunofluorescence assays, we observed Borrelia in all mouse skin and capsule fecal swabs tested, although we could not culture the spirochetes. These results update our previous analysis by revealing that spirochetes can also be visualized in tick excrement. Furthermore, the results emphasize that borrelial contamination by defecation is a possibility, and that caution should be exercised by researchers investigating pathogen/host/vector interactions. The biological significance of the presence of non-culturable Borrelia in tick feces during engorgement is unclear.
莱姆病病原体伯氏疏螺旋体的地方流行周期涉及到硬蜱属的蜱类和脊椎动物。当蜱类吸食血液时，寄生于蜱类中肠内的居留型螺旋体会随着蜱类的唾液被排放到脊椎动物宿主中。在这 4-5 天的吸血期内，硬蜱会将粪便排到宿主的皮肤上。此前，我们在整个饱血期的蜱粪便中都检测到了伯氏疏螺旋体的 DNA。在这项研究中，我们报告了在若虫粪便中检测到伯氏疏螺旋体的微观检查结果。通过免疫荧光检测，我们观察到所有接受检测的鼠皮和囊粪便拭子中都有博氏疏螺旋体，尽管我们无法培养这些螺旋体。这些结果更新了我们之前的分析，表明在蜱类粪便中也可以观察到螺旋体。此外，这些结果强调了粪便中排出的螺旋体可能会造成污染，因此，研究病原体/宿主/媒介相互作用的研究人员应该谨慎行事。在饱血期间，蜱类粪便中存在不可培养的伯氏疏螺旋体的生物学意义尚不清楚。
