Nagore Daniel, García-Sanmartín Josune, García-Pérez Ana L, Juste Ramón A, Hurtado Ana
Department of Animal Health, Instituto Vasco de Investigación y Desarrollo Agrario Berreaga 1, 48160 Derio, Bizkaia, Spain.
Int J Parasitol. 2004 Aug;34(9):1059-67. doi: 10.1016/j.ijpara.2004.05.008.
The genetic diversity and prevalence of virtually all Theileria and Babesia species in a sheep population were studied using a specifically designed reverse line blot macroarray. The amplified hypervariable V4 region of the 18S rRNA gene was hybridised against generic and species-specific probes. In a first screening (Study I), 320 apparently healthy animals corresponding to 32 flocks located in the Basque Country (Northern Spain) were analysed. The survey demonstrated a high prevalence of subclinical infections (64.7%). Three Theileria genotypes were identified, sharing 96.7-97.0% similarity between their 18S rRNA gene sequences: Theileria ovis, Theileria sp. OT1 (99.6% similarity with the recently described pathogenic piroplasm Theileria sp. China 1), and Theileria sp. OT3. Two Babesia species sharing 91.5% similarity were also detected: Babesia ovis and Babesia motasi. The complete 18S rRNA gene sequences of these and other piroplasm species were phylogenetically analysed. Prevalence of piroplasms was also investigated in a second group of 80 sheep from 16 flocks reared in mountain areas that had been heavily exposed to ticks and had suffered a recent abortion episode (Study II). The screening revealed a significantly higher (P < 0.05) prevalence (78.7%) of piroplasm infections compared to Study I. Although the prevalence rates for some piroplasm species were significantly related to abortion (e.g. Theileria sp. OT3), decreases in the red cell parameters were not significant. The widespread distribution of Theileria spp. in the studied sheep population suggests that the parasites involved are of relatively low pathogenicity, in contrast to what has been reported for Theileria sp. China 1 in other countries.
利用专门设计的反向线印迹宏阵列研究了绵羊群体中几乎所有泰勒虫属和巴贝斯虫属物种的遗传多样性和流行情况。18S rRNA基因扩增的高变V4区与通用探针和物种特异性探针进行杂交。在首次筛查（研究I）中，分析了来自位于西班牙北部巴斯克地区的32个羊群的320只表面健康的动物。调查显示亚临床感染的患病率很高（64.7%）。鉴定出三种泰勒虫基因型，它们的18S rRNA基因序列之间具有96.7 - 97.0%的相似性：绵羊泰勒虫、OT1泰勒虫（与最近描述的致病性梨形虫中国泰勒虫1的相似性为99.6%）和OT3泰勒虫。还检测到两种相似性为91.5%的巴贝斯虫物种：绵羊巴贝斯虫和莫氏巴贝斯虫。对这些和其他梨形虫物种的完整18S rRNA基因序列进行了系统发育分析。在第二组来自山区的80只绵羊中也调查了梨形虫的流行情况，这些绵羊来自16个羊群，曾大量接触蜱虫且近期发生过流产事件（研究II）。筛查显示，与研究I相比，梨形虫感染的患病率显著更高（P < 0.05）（78.7%）。尽管某些梨形虫物种的患病率与流产显著相关（例如OT3泰勒虫），但红细胞参数的下降并不显著。泰勒虫属在研究的绵羊群体中的广泛分布表明，与其他国家报道的中国泰勒虫1相比，所涉及的寄生虫致病性相对较低。
