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Abstract：
Haemonchus contortus, a stomach worm, is prevalent in ruminants worldwide. They particularly hamper profitable small ruminant production. Here, we estimate the genetic variation of H. contortus collected from slaughtered goats and sheep from various geographic zones of Bangladesh using multiple genes. To perform this, adult parasites were isolated from the abomasum of slaughtered animals (sheep and goats). Among them, 79 male H. contortus were identified by microscopy. Following the extraction of DNA, ITS-2 and cox1 genes were amplified and subsequently considered for sequencing. After alignment and editing, sequences were analyzed to find out sequence variation, diversity pattern of genes, and population genetics of isolates. Among the sequence data, the analyses identified 19 genotypes of ITS-2 and 77 haplotypes of cox1 genes. The diversity of nucleotides was 0.0103 for ITS-2 and 0.029 for cox1 gene. The dendogram constructed by the genotype and haplotype sequences of H. contortus revealed that two populations were circulating in Bangladesh without any demarcation of host and geographic regions. Analysis of population genetics demonstrated a high flow of genes (89.2 %) within the population of the worm in Bangladesh. The Fst value showed very little amount of genetic difference among the worm populations of Bangladesh but marked genetic variation between different continents. The findings are expected to help explain the risks of anthelmintic resistance and the transmission pattern of the parasite, and also provide a control strategy against H. contortus.
摘要：
Haemonchuscontrortus，一个胃蠕虫,在全世界的反刍动物中普遍存在。他们特别阻碍有利可图的小型反刍动物生产。这里,我们使用多个基因估算了从孟加拉国各个地理区域的屠宰山羊和绵羊中收集的H.contortus的遗传变异。为了执行这个，从屠宰动物（绵羊和山羊）的皱胃中分离出成年寄生虫。其中,通过显微镜鉴定出79只雄性H.contortus。在提取DNA之后,扩增ITS-2和cox1基因,随后考虑用于测序。对齐和编辑后，分析序列以找出序列变异，基因的多样性模式，和分离株的群体遗传学。在序列数据中，分析确定了19个ITS-2基因型和77个cox1基因单倍型。ITS-2的核苷酸多样性为0.0103，cox1基因的核苷酸多样性为0.029。由H.contortus的基因型和单倍型序列构建的柱状图显示，两个种群在孟加拉国流通，没有对宿主和地理区域进行任何划分。种群遗传学分析表明，孟加拉国蠕虫种群中的基因流量很高（89.2％）。Fst值显示孟加拉国蠕虫种群之间的遗传差异很小，但不同大陆之间的遗传变异明显。这些发现预计将有助于解释驱虫药耐药性的风险和寄生虫的传播模式，并提供了针对H.contortus的控制策略。
