Ketter-Ratzon Dafna, Tirosh-Levy Sharon, Nachum-Biala Yaarit, Saar Tal, Qura'n Lara, Zivotofsky Doni, Abdeen Ziad, Baneth Gad, Steinman Amir
Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel.
Vet Practice, Mechalkey Hamayim 1, Jerusalem 93222, Israel.
Ticks Tick Borne Dis. 2017 Jun;8(4):499-505. doi: 10.1016/j.ttbdis.2017.02.010. Epub 2017 Mar 4.
Equine theileriosis caused by Theileria equi is endemic in the Middle East, where it causes a severe disease as well as widespread subclinical infection. The aim of this study was to evaluate the diversity of T. equi genotypes in Israel and the neighboring Palestinian Authority and Jordan. Blood samples from 355 horses from Israel, the Palestinian Authority and Jordan were tested for the prevalence of T. equi DNA. Two hundred and fourteen (60%) were found positive for T. equi infection by PCR. Of those, the 18S rRNA (1458bp) and the EMA-1 (745bp) genes of T. equi were sequenced from 15 horse samples that represent Israel's geographical distribution together with four samples from the Palestinian Authority and two from Jordan. The results were used for genotype characterization and phylogenetic analysis of T. equi in the equine population in Israel and its surroundings. Three 18S rRNA genotype clades were found in Israel (A, C and D) with clade D being the most prevalent and included all four isolates from the PA. In contrast, the EMA-1 gene showed little diversity with all sequences clustering in the same clade apart from one Jordanian sequence. Results suggest that although the Israeli horse population is small and relatively confined geographically, it is probable that the genetic variability, which was found among Israeli horses, is a result of introduction of horses from other countries. It also suggests that the EMA-1 gene is probably not a good target for the evaluation of variance in T. equi populations. Characterization of the different genotypes prevalent in a certain region is important in order to map out the intra-species sequence heterogeneity of the parasite, which is needed in order to develop new diagnostic tools and vaccines.
由马泰勒虫（Theileria equi）引起的马泰勒虫病在中东地区流行，该病会引发严重疾病以及广泛的亚临床感染。本研究旨在评估以色列、邻国巴勒斯坦权力机构和约旦的马泰勒虫基因型多样性。对来自以色列、巴勒斯坦权力机构和约旦的355匹马的血液样本进行马泰勒虫DNA流行率检测。通过聚合酶链反应（PCR）发现，214匹（60%）马的马泰勒虫感染呈阳性。其中，从代表以色列地理分布的15份马样本以及来自巴勒斯坦权力机构的4份样本和来自约旦的2份样本中，对马泰勒虫的18S核糖体RNA（1458bp）和EMA-1（745bp）基因进行测序。研究结果用于对以色列及其周边地区马群中马泰勒虫进行基因型鉴定和系统发育分析。在以色列发现了三个18S rRNA基因型分支（A、C和D），其中D分支最为普遍，包括来自巴勒斯坦权力机构的所有四个分离株。相比之下，EMA-1基因的多样性较小，除了一个约旦序列外，所有序列都聚集在同一个分支中。结果表明，尽管以色列的马群数量较少且地理分布相对局限，但以色列马群中发现的遗传变异性可能是其他国家马匹引入的结果。这也表明，EMA-1基因可能不是评估马泰勒虫种群变异的良好靶点。确定某一地区流行的不同基因型对于描绘该寄生虫种内序列异质性很重要，而这对于开发新的诊断工具和疫苗是必要的。
