The genus Anaplasma: new challenges after reclassification
The genus Anaplasma: new challenges after reclassification
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DOI：
10.20506/rst.34.2.2381
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发表时间：
2015-08-01
影响因子：
0.6
通讯作者：
Cabezas-Cruz, A.
中科院分区：
文献类型：
--
作者：
Kocan, K. M.;de la Fuente, J.;Cabezas-Cruz, A.
无形体属（Anaplasma）是无形体科（Anaplasmataceae）的四个不同属之一，其是由蜱介导的专性细胞内病原体，并且仅在宿主细胞质中的寄生虫空泡内发现。2001年立克次体目的重新分类扩大了无形体属，该属以前包含反刍动物特异性宿主的病原体（A。marginale，A. centrale和A. ovis），通过添加A.嗜吞噬细胞菌，是先前被归类为埃立克体（Ehrlichia）的三种生物体的统一（E. aqui、艾美耳球虫E.嗜吞噬细胞菌和人粒细胞埃里希体病的未命名因子）。无形体属还包括A. bovis（原E. bovis）、牛肝菌A.扁虫（原E. platys）和鸡白痢埃及菌（Aegyptianella pullorum）。尽管重组生物体的基因组相关性，但其生物学的许多方面是不同的，包括其宿主特异性，宿主细胞偏好，主要表面蛋白（MSP）和蜱载体。本文主要介绍两种最重要的病原体：A. marginale，引起牛无形体病;嗜吞噬细胞菌，绵羊蜱传热的病原体和人粒细胞无形体病，一种新出现的人类蜱传疾病。对于这两种病原体，菌株多样性比以前认识到的要大得多。虽然发现MSP在系统发育研究和菌株鉴定中是有用的，但发现高度保守的MSP影响血清学测试的特异性。这两种重要病原体的比较突出了来自重新分类和分子分析的挑战和见解，这两者都对诊断和控制策略的开发和评估具有影响。
The genus Anaplasma is one of four distinct genera in the family Anaplasmataceae, which are obligate intracellular pathogens vectored by ticks and found exclusively within parasitophorous vacuoles in the host cell cytoplasm. The 2001 reclassification of the order Rickettsiales expanded the genus Anaplasma, which previously contained pathogens that were host specific for ruminants (A. marginale, A. centrale and A. ovis), by adding A. phagocytophilum, a unification of three organisms previously classified as Ehrlichia (E. aqui, E. phagocytophila and the unnamed agent of human granulocytic ehrlichiosis). Also included in the genus Anaplasma were A. bovis (formerly E. bovis), A. platys (formerly E. platys) and Aegyptianella pullorum. Despite the genomic relatedness of the regrouped organisms, many aspects of their biology are diverse, including their host specificity, host cell preferences, major surface proteins (MSPs) and tick vectors. This review focuses on the two most important pathogens: A. marginale, which causes bovine anaplasmosis, and A. phagocytophilum, the aetiologic agent of tick-borne fever in sheep and human granulocytic anaplasmosis, an emerging tick-borne disease of humans. For both pathogens, strain diversity is much greater than previously recognised. While MSPs were found to be useful in phylogenetic studies and strain identification, highly conserved MSPs were found to affect the specificity of serologic tests. Comparison of these two important pathogens highlights the challenges and insight derived from reclassification and molecular analysis, both of which have implications for the development and evaluation of diagnosis and control strategies.