Parasitology Laboratory, Department of Zoology, P.U., Chandigarh, India.
Acta Parasitol. 2023 Jun;68(2):359-371. doi: 10.1007/s11686-023-00671-4. Epub 2023 Mar 28.
Tapeworms of Avitellina spp. are among those gastrointestinal parasitic helminths which infect wild and domestic ruminants worldwide leading to various clinical manifestations in the ruminant hosts, thereby causing considerable economic losses in livestock production. While these worms are among the major constraints in ruminant livestock raising, there is very meagre molecular information available making their identity error-prone. This study aimed to provide insights into the genetic characterization of these economically important tapeworms.
In the present study, we examined 480 guts of slaughtered goats (n = 413) and sheep (n = 67) of which 74 guts were found infected with anoplocephalid cestodes (sheep gut:18; goat gut:56). A total of 27 Avitellina lahorea worms (19 from goat and 8 from sheep) were isolated, fixed, relaxed and stained using Gower's carmine stain. For molecular analyses, the genomic DNA was extracted and fragments of cytochrome c oxidase subunit 1 (cox1) gene, internal transcribed spacer1-5.8S ribosomal RNA (ITS1-5.8S rRNA) gene, and small subunit ribosomal RNA (18S rRNA) gene were amplified and sequenced.
Based on snail-shaped paruterine organs and other morphological and morphometric features, the worms were identified as Avitellina lahorea. The phylogenetic analyses, based on our original cox1 gene sequence and those available from NCBI GenBank, showed Avitellina tapeworms as a sister lineage of Thysaniezia with 14 to 17% genetic divergence. Molecular analyses of 18S rRNA gene sequences depicted the present isolate as one of the species of the genus Avitellina clustering with A. centripunctata as a separate species in the phylogenetic tree with 92% homogeneity in sequences. In conjunction with existing data of internal transcribed spacer1-5.8S rRNA (ITS1-5.8S rRNA) gene, the phylogenetic analysis placed the present isolate among the anoplocephalids as one of the species.
The present study is the first molecular report on A. lahorea isolated from sheep and goats with the simultaneous use of a morphological approach, and certainly contributes to bridging the existing gaps in the understanding of these economically important parasites.
Avitellina 属绦虫是感染世界范围内野生和家养反刍动物的胃肠道寄生性蠕虫之一，导致反刍宿主出现各种临床症状，从而给畜牧业生产造成相当大的经济损失。虽然这些蠕虫是反刍家畜饲养的主要限制因素之一，但可用的分子信息非常少，导致它们的身份容易出错。本研究旨在提供对这些具有重要经济意义的绦虫的遗传特征的深入了解。
在本研究中，我们检查了 480 个屠宰山羊（n=413）和绵羊（n=67）的肠道，其中 74 个肠道发现感染有棘头虫（绵羊肠道：18；山羊肠道：56）。共分离出 27 条 Avitellina lahorea 蠕虫（19 条来自山羊，8 条来自绵羊），用 Gower 胭脂红染色固定、松弛和染色。为了进行分子分析，提取基因组 DNA，扩增并测序细胞色素 c 氧化酶亚基 1（cox1）基因、内部转录间隔区 1-5.8S 核糖体 RNA（ITS1-5.8S rRNA）基因和小亚基核糖体 RNA（18S rRNA）基因。
根据蜗牛形的副子宫器官和其他形态和形态特征，这些蠕虫被鉴定为 Avitellina lahorea。基于我们的原始 cox1 基因序列和来自 NCBI GenBank 的其他序列的系统发育分析显示，Avitellina 绦虫与 Thysaniezia 是姐妹群，遗传距离为 14%至 17%。18S rRNA 基因序列的分子分析表明，本分离株是 Avitellina 属的一个物种，与 A. centripunctata 作为一个单独的物种聚类，序列同源性为 92%。结合现有的内部转录间隔区 1-5.8S rRNA（ITS1-5.8S rRNA）基因数据，系统发育分析将本分离株归入棘头虫属的一个物种。
本研究是首次使用形态学方法对从绵羊和山羊中分离出的 A. lahorea 进行的分子报告，肯定有助于弥合对这些具有重要经济意义的寄生虫的理解差距。
