Department of Medical Parasitology and Mycology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
Department of Biostatistics, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
BMC Vet Res. 2021 Dec 4;17(1):371. doi: 10.1186/s12917-021-03086-3.
This study was carried out to investigate the prevalence and analyze the molecular characteristics based on the internal transcribed spacer (ITS) 2 region of the ribosomal RNA (RNA) gene of trichostrongylid nematodes in different ruminants from Guilan province, northern of Iran.
The gastrointestinal tracts of 144 ruminants including 72 cattle, 59 sheep, and 13 goats were collected from an abattoir in Guilan province during July to September 2018. After isolation the helminths, male specimens were identified based on morphological parameters. PCR and partial sequencing of the ITS2 fragment were conducted. After phylogenetic analysis, the intraspecific and interspecific differences were calculated.
The prevalence of total infections with the nematodes was 38.9, 74.6 and 84.6% among cattle, sheep and goats, respectively. Eleven species of trichostrongylid nematodes including Haemonchus contortus, Marshallagia marshalli, Trichostrongylus axei, T. colubriformis, T. vitrinus, Ostertagia trifurcata, Teladorsagia circumcincta, Marshallagia occidentalis, O. lyrata, O. ostertagi, and Cooperia punctate were recovered from the ruminants. The most prevalent trichostrongyloid nematodes in cattle, sheep and goats were O. ostertagi (26.4%), M. marshalli (64.4%) and T. circumcincta (69.2%), respectively. Phylogenetic tree was discriminative for Trichostrongylidae family, while phylogenetic analysis of the ITS2 gene represented low variations and no species identification of Haemonchidae and Cooperiidae families.
This study suggests the high prevalence and species diversity of trichostrongyloid nematodes in different ruminants, indicating the importance of implement antiparasitic strategies in north regions of Iran. As well, this study showed that the ITS2 fragment is not a discriminative marker for Haemonchidae and Cooperiidae families, and investigation of other genetic markers such as mitochondrial genes would be more valuable for better understanding of their phylogenetic relationships.
本研究旨在调查伊朗北部吉兰省不同反刍动物中基于核糖体 RNA（RNA）基因内转录间隔区（ITS）2 区域的 Trichostrongylid 线虫的流行情况并分析其分子特征。
2018 年 7 月至 9 月，从吉兰省一家屠宰场采集了 144 只反刍动物的胃肠道，包括 72 头牛、59 只绵羊和 13 只山羊。分离出寄生虫后，根据形态学参数鉴定雄性样本。进行 PCR 和 ITS2 片段的部分测序。在进行系统发育分析后，计算了种内和种间差异。
牛、绵羊和山羊的总线虫感染率分别为 38.9%、74.6%和 84.6%。从反刍动物中分离出 11 种 Trichostrongylid 线虫，包括捻转血矛线虫、马歇尔线虫、奥斯特线虫、弯口线虫、细颈线虫、Ostertagia trifurcata、泰氏阔盘吸虫、马歇尔线虫、O. lyrata、O. ostertagi 和 Cooperia punctata。牛、绵羊和山羊中最常见的 Trichostrongyloid 线虫分别为 O. ostertagi（26.4%）、M. marshalli（64.4%）和 T. circumcincta（69.2%）。系统发育树可区分 Trichostrongylidae 科，而 ITS2 基因的系统发育分析显示低变异性，无法识别 Haemonchidae 和 Cooperiidae 科的物种。
本研究表明，伊朗北部不同反刍动物中 Trichostrongylid 线虫的流行率和物种多样性较高，表明在该地区实施驱虫策略的重要性。此外，本研究表明 ITS2 片段不是 Haemonchidae 和 Cooperiidae 科的鉴别标记，调查其他遗传标记，如线粒体基因，对于更好地了解它们的系统发育关系将更有价值。
