Yabsley Michael J, Murphy Staci M, Luttrell M Page, Wilcox Benjamin R, Ruckdeschel Carol
Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, United States.
Vet Microbiol. 2008 Oct 15;131(3-4):301-8. doi: 10.1016/j.vetmic.2008.04.004. Epub 2008 Jun 3.
"Candidatus Neoehrlichia mikurensis" has been reported from a variety of rodent and Ixodes tick species in Europe and Asia. Recently, an ehrlichial organism closely related to "Candidatus Neoehrlichia mikurensis" was cultured from a raccoon (Procyon lotor) from Georgia, USA. To determine prevalence and distribution, we conducted a molecular survey of free-ranging raccoons (n=197) from 10 populations in 3 states and found that infections were common in tick-infested populations (50-94%). In an effort to determine the host range of this organism, 10 species of rodents (n=137) trapped in 3 areas where positive raccoons had been detected were tested; all were negative. In addition, captive bred raccoons and several common laboratory animals (mice, rats, and rabbits) were inoculated with the raccoon ehrlichial isolate (strain RAC413). Raccoons became infected with the culture isolate but all other hosts were refractory to infection. The 16S rRNA gene sequence (1379bp) of the RAC413 isolate was most similar (98.4-98.8%) to members of the "Candidatus Neoehrlichia mikurensis" group and phylogenetic analysis confirmed this organism was related to, but distinct from, "Candidatus Neoehrlichia mikurensis". Based on the molecular and natural history uniqueness of this organism from raccoons, we propose that this represents a novel species in the "Candidatus Neoehrlichia" group of ehrlichial organisms.
在欧洲和亚洲，多种啮齿动物及硬蜱属蜱类中均有“米库新立克次体（暂未培养成功）”的报道。最近，从美国佐治亚州的一只浣熊（北美浣熊）体内培养出了一种与“米库新立克次体（暂未培养成功）”密切相关的埃立克体生物。为确定其流行率和分布情况，我们对来自3个州10个种群的197只野生浣熊进行了分子调查，发现蜱虫寄生的种群中感染情况很常见（50%-94%）。为确定这种生物的宿主范围，我们检测了在已检测到阳性浣熊的3个区域捕获的10种啮齿动物（共137只）；结果均为阴性。此外，我们用浣熊埃立克体分离株（菌株RAC413）接种了圈养繁殖的浣熊和几种常见实验动物（小鼠、大鼠和兔子）。浣熊被该培养分离株感染，但所有其他宿主均对感染具有抗性。RAC413分离株的16S rRNA基因序列（1379bp）与“米库新立克次体（暂未培养成功）”组的成员最为相似（98.4%-98.8%），系统发育分析证实这种生物与“米库新立克次体（暂未培养成功）”相关，但又有所不同。基于这种来自浣熊的生物在分子和自然史方面的独特性，我们提议将其归为“新立克次体（暂未培养成功）”组埃立克体生物中的一个新物种。
