Molecular characterization of Trypanosoma (Megatrypanum) spp. infecting cattle (Bos taurus), white-tailed deer (Odocoileus virginianus), and elk (Cervus elaphus canadensis) in the United States
Molecular characterization of Trypanosoma (Megatrypanum) spp. infecting cattle (Bos taurus), white-tailed deer (Odocoileus virginianus), and elk (Cervus elaphus canadensis) in the United States
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DOI：
10.1016/j.vetpar.2013.04.037
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发表时间：
2013-10-18
影响因子：
2.6
通讯作者：
Holman, Patricia J.
中科院分区：
文献类型：
--
作者：
Fisher, Amanda C.;Schuster, Greta;Holman, Patricia J.
在美国，牛的一般非致病性锥虫被命名为牛锥虫（Megatrypanum），在形态上与最初在骡鹿和麋鹿中描述的锥虫（M.）宫颈锥虫（M.）区分开来。利用各种分子标记对巨锥虫进行系统发育研究，揭示了两个谱系，分别命名为TthI和TthII，每个谱系中都有几个基因型。然而，到目前为止，关于T. theileri的遗传数据非常有限，而美国野生有蹄类动物中发现的Megatrypanum锥虫的遗传数据则非常有限。本研究通过核蛋白体DNA （rDNA）序列分析比较了美国牛（Bos taurus）、白尾鹿（Odocoileus virginianus）和麋鹿（Cervus elaphus canadensis）的分离株，并调查了它们在德克萨斯州南部县的牛和WTD中的发病率。系统发育分析表明牛和牛的锥虫有明显的分离。谱系I和II在美国牛和WTD寄生虫中都有代表。谱系I牛分离株为先前描述的基因型，而WTD和麋鹿分离株为两种不同于牛锥虫的新基因型。ⅱ系牛分离物为先前报道的一种基因型，与WTD分离物为一种新的基因型。在德克萨斯州南部的拉萨尔、斯塔尔、韦伯和萨帕塔县，51.8%的白尾鹿经18S rDNA PCR检测为锥虫阳性。在韦伯县接受筛查的牛中，35.4%呈阳性。在筛选动物时，德克萨斯州南部普遍存在干旱条件，这表明除了蜱虫（Lipoptena mazamae）和虻蝇（Tabanus spp.和Haematopota spp.）之外，还可能存在锥虫病媒介。(C) 2013 Elsevier B.V.版权所有
In the United States, the generally non-pathogenic trypanosome of cattle is designated Trypanosoma (Megatrypanum) theileri and is distinguished morphologically from Trypanosoma (M.) cervi, a trypanosome originally described in mule deer and elk. Phylogenetic studies of the Megatrypanum trypanosomes using various molecular markers reveal two lineages, designated TthI and TthII, with several genotypes within each. However, to date there is very limited genetic data for T. theileri, and none for the Megatrypanum trypanosomes found in wild ungulates, in the U.S. In this study U.S. isolates from cattle (Bos taurus), white-tailed deer (Odocoileus virginianus) (WTD), and elk,(Cervus elaphus canadensis) were compared by ribosomal DNA (rDNA) sequence analysis and their incidence in cattle and WTD in south Texas counties was investigated. Phylogenetic analyses showed clear separation of the bovine and cervine trypanosomes. Both lineages I and II were represented in the U.S. cattle and WTD parasites. Lineage I cattle isolates were of a previously described genotype, whereas WTD and elk isolates were of two new genotypes distinct from the cattle trypanosomes. The cattle isolate of lineage II was of a previously reported genotype and was divergent from the WTD isolate, which was of a new genotype. In La Salle, Starr, Webb, and Zapata counties in south Texas a total of 51.8% of white-tailed deer were positive for trypanosomes by 18S rDNA PCR. Of the cattle screened in Webb County, 35.4% were positive. Drought conditions prevailing in south Texas when the animals were screened suggest the possibility of a vector for Trypanosoma other than the ked (Lipoptena mazamae) and tabanid flies (Tabanus spp. and Haematopota spp.). (C) 2013 Elsevier B.V. All rights reserved.