Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA.
Vet Parasitol. 2011 May 11;177(3-4):298-304. doi: 10.1016/j.vetpar.2010.11.052. Epub 2010 Dec 4.
Serologic and molecular evidence suggest that white-tailed deer in South Texas and North Mexico carry the agents of bovine babesiosis, Babesia bovis and Babesia bigemina. To determine if white-tailed deer in central Texas, which is outside the known occurrence of the vector tick at this time, harbor these parasites, blood samples from free-ranging and captive white-tailed deer (Odocoileus virginianus) in Tom Green County were tested by polymerase chain reaction (PCR) assays for B. bovis and B. bigemina 18S rDNA. Of the 25 samples tested, three (12%) were positive by nested PCR for B. bovis. This identity was confirmed by sequence analysis of the cloned 18S rDNA PCR product. Further confirmation was made by sequence analysis of the rRNA internal transcribed spacer (ITS) 1, 5.8S rRNA gene, and ITS 2 genomic region in two (representing samples from two different ranches) of the B. bovis positive samples. Three samples were positive by B. bigemina nested PCR, but sequencing of the cloned products confirmed only one animal positive for B. bigemina; Theileria spp. DNA was amplified from the other two animal samples. In addition to Theileria spp., two genotypically unique Babesia species sequences were identified among the cloned sequences produced by the B. bigemina primers in one sample. Phylogenetic analysis showed no separation of the deer B. bovis or B. bigemina 18S rDNA, or deer B. bovis ITS region sequences from those of bovine origin. Clarification of the possible role of white-tailed deer as reservoir hosts in maintaining these important pathogens of cattle is critical to understanding whether or not deer contribute to the epidemiology of bovine babesiosis.
血清学和分子证据表明，南得克萨斯州和北墨西哥的白尾鹿携带牛巴贝斯虫病原体，即双芽巴贝斯虫和牛巴贝斯虫。为了确定中得克萨斯州的白尾鹿是否携带这些寄生虫，中得克萨斯州目前没有已知的媒介蜱虫存在，该州汤格林县的自由放养和圈养白尾鹿（Odocoileus virginianus）的血液样本通过聚合酶链反应（PCR）检测了双芽巴贝斯虫和牛巴贝斯虫 18S rDNA。在检测的 25 个样本中，有 3 个（12%）通过巢式 PCR 对双芽巴贝斯虫呈阳性。这一身份通过对克隆的 18S rDNA PCR 产物进行序列分析得到了确认。进一步的确认是通过对两个阳性样本（代表来自两个不同牧场的样本）的 rRNA 内部转录间隔区（ITS）1、5.8S rRNA 基因和 ITS 2 基因组区域的序列分析来完成的。有 3 个样本通过牛巴贝斯虫巢式 PCR 呈阳性，但对克隆产物进行测序仅确认了一个动物对牛巴贝斯虫呈阳性；在另外两个动物样本中检测到了泰勒虫属 DNA。除了泰勒虫属之外，在通过牛巴贝斯虫引物产生的克隆序列中，在一个样本中还鉴定出了两种基因型独特的巴贝斯虫序列。系统发育分析显示，鹿的双芽巴贝斯虫或牛巴贝斯虫 18S rDNA 或鹿的双芽巴贝斯虫 ITS 区序列与牛源序列没有分离。澄清白尾鹿作为这些重要牛病原体的维持宿主的可能作用，对于了解白尾鹿是否有助于牛巴贝斯虫病的流行病学至关重要。
