Genetic diversity of Ehrlichia ruminantium in Amblyomma variegatum ticks and small ruminants in The Gambia determined by restriction fragment profile analysis
Genetic diversity of Ehrlichia ruminantium in Amblyomma variegatum ticks and small ruminants in The Gambia determined by restriction fragment profile analysis
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DOI：
10.1016/j.vetmic.2007.06.010
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发表时间：
2008-01-01
影响因子：
3.3
通讯作者：
Geysen, Dirk
中科院分区：
文献类型：
--
作者：
Faburay, Bonto;Jongejan, Frans;Geysen, Dirk
了解宿主和病媒群体中反刍埃利希体的遗传多样性是撒哈拉以南非洲传统牲畜系统通过疫苗接种控制心水病的重要前提。我们的研究分两个阶段进行：(i)评估基于E. ruminantium map1编码序列的PCR-RFLP分析作为表征遗传多样性的歧视性工具的有效性；（ii）将该技术应用于冈比亚、苏丹-几内亚（SG）、西苏丹-萨赫勒（WSS）和东苏丹-萨赫勒（ESS）三个主要农业生态区的变异双盲蜱和小反刍动物的野外样本，以表征该生物的基因型多样性。在不同菌株之间观察到限制性片段长度多态性，支持PCR-RFLP技术在研究该生物遗传多样性方面的有效性。限制性内切酶map1图谱分析表明，冈比亚存在多种基因型（至少有11种），其中WSS区和SG区基因型较多。与Kerr Seringe基因型（DQ333230）相似的谱显示出最高的分布频率，出现在所有三个农业生态区的地点，从而使该菌株成为交叉保护研究中进一步表征的合适候选菌株。另外三种基因型表现出相对较高的分布频率，并且在所有三个区域都存在，这使得它们对分离和随后的表征同样重要。研究表明反刍E. ruminantium基因型混合感染在反刍动物和蜱中发生。(C) 2007 Elsevier B.V.版权所有
Understanding genetic diversity of Ehrlichia ruminantium in host and vector populations is an important prerequisite to controlling heartwater by vaccination in traditional livestock systems in sub-Saharan Africa. We carried out a study in two phases: (i) evaluating the usefulness of the PCR-RFLP assay based on the map1 coding sequence of E. ruminantium as a discriminatory tool to characterise genetic diversity, (ii) applying the technique to field samples from Amblyomma variegatum ticks and small ruminants to characterise genotypic diversity of the organism in three main agroecological zones of The Gambia, Sudano-Guinean (SG), Western Sudano-Sahelian (WSS) and Eastern Sudano-Sahelian (ESS). Restriction fragment length polymorphisms were observed among different strains of E. ruminantium supporting the usefulness of the PCR-RFLP technique for studying genetic diversity of the organism. Restriction enzyme map1 profile analysis indicated the presence in The Gambia of multiple genotypes (at least: 11) of E. ruminantium with sites in the WSS and SG zones showing comparatively high number of diverse genotypes. Profiles similar to the Kerr Seringe genotype (DQ333230) showed the highest distribution frequency, being present at sites in all three agroecological zones, thereby making the strain a suitable candidate for further characterisation in cross-protection studies. An additional three genotypes showed relatively high distribution frequency and were present in all three zones making them equally important for isolation and subsequent characterisation. The study demonstrated the occurrence of mixed infections with E. ruminantium genotypes in ruminants and ticks. (C) 2007 Elsevier B.V. All rights reserved.