Department of Microbiology and Parasitology, Sher-e-Bangla Agricultural University, Sher-e-Bangla Nagar, Dhaka, 1207, Bangladesh.
Department of Pathology and Parasitology, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Khulshi, Chittagong, 4225, Bangladesh.
Parasitol Res. 2023 Dec;122(12):3101-3107. doi: 10.1007/s00436-023-08000-4. Epub 2023 Oct 19.
Haemonchus contortus is a blood-sucking gastrointestinal nematode that infects all ruminants and causes significant economic losses in production. Characterizing the genetic variability of H. contortus populations is crucial for understanding patterns of disease transmission and developing effective control strategies against haemonchosis. This study aimed to identify the genetic variability of H. contortus isolates in small ruminants from slaughterhouses in Bangladesh. During January to December 2015, 400 abomasa samples were collected and 186 were found to be positive for Haemonchus. A 321-bp fragment of the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA and an 800-bp fragment of the mitochondrial nicotinamide dehydrogenase subunit-4 gene (nad4) were amplified using polymerase chain reaction (PCR) and directly sequenced. The results showed 10 genotypes (ITS-2) and 45 haplotypes (nad4) among the 186 worms. The sequences were 98.5 to 100% identical to reference sequences from the GenBank database. ITS-2 sequence analysis revealed four nucleotide substitutions at positions 30, 41, 42, and 216. There was one transition (C/T) at position 42 and three transversions (C/A at position 30, G/C at position 41, and T/A at position 216). The nad4 gene sequences showed 15 substitutions, all of which were transitions. The pairwise distance of ITS-2 between H. contortus populations ranged from 0.005 to 1.477. The nucleotide diversity (μ) among the populations was 0.009524 using ITS-2 and 0.00394 using nad4. This study indicated low genetic deviation among H. contortus populations in Bangladesh.
捻转血矛线虫是一种寄生在所有反刍动物的胃肠道内的吸血寄生虫，可导致生产中重大的经济损失。 描述捻转血矛线虫种群的遗传变异对于了解疾病传播模式和制定有效的抗血矛线虫病控制策略至关重要。 本研究旨在鉴定来自孟加拉国屠宰场的小反刍动物捻转血矛线虫分离株的遗传变异。 在 2015 年 1 月至 12 月期间，采集了 400 份皱胃样本，发现 186 份样本对 Haemonchus 呈阳性。 使用聚合酶链反应（PCR）扩增了核核糖体 DNA 的第二内部转录间隔区（ITS-2）的 321bp 片段和线粒体烟酰胺脱氢酶亚单位-4 基因（nad4）的 800bp 片段，并直接进行了测序。 结果显示，在 186 条蠕虫中存在 10 种基因型（ITS-2）和 45 种单倍型（nad4）。 序列与 GenBank 数据库中的参考序列的相似度为 98.5 至 100％。 ITS-2 序列分析显示，在位置 30、41、42 和 216 处有 4 个核苷酸取代。 位置 42 处有一个转换（C/T），位置 30、41 和 216 处有三个颠换（C/A、G/C 和 T/A）。 nad4 基因序列显示有 15 个取代，均为转换。 利用 ITS-2 进行分析时，捻转血矛线虫种群之间的 ITS-2 成对距离在 0.005 至 1.477 之间。 种群之间的核苷酸多样性（μ）利用 ITS-2 为 0.009524，利用 nad4 为 0.00394。 本研究表明，孟加拉国捻转血矛线虫种群的遗传变异较低。
