Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, México DF 07360, Mexico.
Infect Genet Evol. 2009 Dec;9(6):1092-101. doi: 10.1016/j.meegid.2009.09.007. Epub 2009 Sep 26.
Bovine anaplasmosis, caused by the rickettsia Anaplasma marginale, has a worldwide distribution and is the cause of great economic losses in developing countries where it is highly endemic. Transmission is carried mainly by ixodid ticks: Dermacentor spp. and Rhipicephalus (Boophilus) spp. Mechanical transmission is important in disseminating the disease within and across herds. The relationship between the rickettsia, the host and the vector is complex. Several surface proteins (Msps) have been described with functions that span from adhesins towards the erythrocyte and tick cells to evasion of the immune system of the host through the generation of antigenic variants. Biologic transmission of A. marginale through Dermacentor ticks has been well studied but many questions are unresolved as to how this organism spreads within and across herds and little is known about the role Rhipicephalus (Boophilus) ticks play in transmission in the Americas. Mechanical transmission in the absence of ticks and lack of transmission through ticks are questions that need to be addressed. Phylogenetic studies of the rickettsia show wide antigenic and genetic mosaics which affects the design of new vaccines. In the present work we will discuss the molecular elements in the relationship between the rickettsia, the tick and the mammalian host associated to the distribution and persistence of the pathogen in nature.
牛无浆体病由马泰勒虫引起，分布广泛，在高度流行的发展中国家造成了巨大的经济损失。传播主要通过硬蜱属（Ixodidae）的蜱虫：璃眼蜱属（Dermacentor）和扇头蜱属（Rhipicephalus）（Boophilus）。机械传播在疾病在牛群内和牛群间的传播中起着重要作用。立克次体、宿主和媒介之间的关系很复杂。已经描述了几种具有从黏附素到红细胞和蜱细胞功能的表面蛋白（Msps），以通过产生抗原变体来逃避宿主的免疫系统。通过璃眼蜱属的生物传播已得到很好的研究，但关于该生物如何在牛群内和牛群间传播以及关于扇头蜱属（Boophilus）蜱在美洲传播中的作用知之甚少，仍有许多问题尚未解决。在没有蜱虫的情况下的机械传播以及不通过蜱虫传播是需要解决的问题。对立克次体的系统发育研究表明，其存在广泛的抗原和遗传镶嵌现象，这影响了新疫苗的设计。在本工作中，我们将讨论与病原体在自然界中的分布和持续存在相关的立克次体、蜱虫和哺乳动物宿主之间关系中的分子要素。
