Higazi T B, Katholi C R, Mahmoud B M, Baraka O Z, Mukhtar M M, Qubati Y A, Unnasch T R
Division of Geographic Medicine, BBRB 203, University of Alabama at Birmingham, 35294, USA.
Exp Parasitol. 2001 Jan;97(1):24-34. doi: 10.1006/expr.2000.4589.
Onchocerciasis in Sudan exists in three distinct foci which exhibit differing clinical presentations. Previous studies have demonstrated that a tandemly repeated Onchocerca sequence family with a unit repeat length of 150 bp (the O-150 family) is a useful marker for deducing relationships among different O. volvulus populations. In the current study, the O-150 repeat families of O. volvulus from Sudan were analyzed and compared to each other and to those of parasites from West Africa. Similar to West African and American O. volvulus, the O-150 families of the Sudanese parasites could be divided into clusters within which little or no intracluster variation was evident, suggesting that the O-150 family in these parasites was subject to the forces of concerted evolution. Statistical analysis of the O-150 families from the different Sudanese parasite isolates, employing a nested algorithm based on an analysis of variance, revealed that O. volvulus endemic to the northern focus at Abu Hamed were significantly different from all other O. volvulus populations examined to date. In contrast, parasites from the southern and eastern foci of Sudan were indistinguishable from those endemic to the West African savanna. The significance of these data are discussed in light of knowledge of the biogeography and biology of transmission of O. volvulus in Africa.
苏丹的盘尾丝虫病存在于三个不同的疫源地，临床表现各异。以往研究表明，一个单位重复长度为150 bp的串联重复盘尾丝虫序列家族（O-150家族）是推断不同旋盘尾丝虫种群间关系的有用标记。在本研究中，对来自苏丹的旋盘尾丝虫的O-150重复家族进行了分析，并相互比较，还与来自西非的寄生虫的O-150重复家族进行了比较。与西非和美洲的旋盘尾丝虫相似，苏丹寄生虫的O-150家族可分为多个簇，簇内几乎没有明显的变异，这表明这些寄生虫中的O-150家族受到协同进化力量的影响。采用基于方差分析的嵌套算法，对来自不同苏丹寄生虫分离株的O-150家族进行统计分析，结果显示，位于阿布哈梅德北部疫源地的旋盘尾丝虫与迄今检测的所有其他旋盘尾丝虫种群存在显著差异。相比之下，苏丹南部和东部疫源地的寄生虫与西非稀树草原的地方流行寄生虫无法区分。根据非洲旋盘尾丝虫生物地理学和传播生物学的知识，对这些数据的意义进行了讨论。
