Faculty of Medicine, Department of Parasitology, Adnan Menderes University, Aydin, Turkey.
Recombinant DNA and Recombinant Protein Application and Research Center, Adnan Menderes University, Aydin, Turkey.
Zoonoses Public Health. 2022 Dec;69(8):897-903. doi: 10.1111/zph.12986. Epub 2022 Jul 7.
Dientamoeba fragilis is a flagellated protozoan with amoeba-like morphology that inhabits the human gastrointestinal tract. It is endemic in a vast geography around the world, including developed countries. There are limited studies on non-human hosts of the parasite, and suitable hosts have not been clarified. The parasite has been detected in non-human primates, pigs, cats, dogs and rats. There is no study in the literature investigating and detecting the presence of this parasite in cattle. In this study, stool samples taken from 163 different cattle and calves from 11 different farms between March 2017 and May 2022 were examined for the detection of D. fragilis via PCR. Trichrome staining was performed on all PCR-positive samples. The isolates with the expected amplicon size were sequenced using the 18S ribosomal RNA region, and their genotypes were determined by BLAST analysis. Sequences were analysed with the most similar and reference sequences in the literature, forming a phylogenetic tree. We detected D. fragilis in 31 (19.01%) of the 163 stool samples. D. fragilis cysts/trophozoites were detected by trichrome staining method in six of 31 samples. All PCR products selected for molecular analysis from positive samples had the same nucleotide sequence. As a result of BLAST analysis, all sequences were determined to belong to D. fragilis genotype 1. This study determined for the first time that cattle are suitable hosts for D. fragilis. Furthermore, the parasite subtype we detected belongs to genotype 1, which is the most common type in humans, suggesting that the parasite may have a zoonotic character. Our result is important in terms of the epidemiology of the parasite, as the mode of transmission is controversial, and available data on its suitable hosts are limited.
脆弱双核阿米巴是一种具有阿米巴样形态的鞭毛虫原生动物，栖息在人类的胃肠道中。它在世界各地广泛流行，包括发达国家。关于寄生虫的非人类宿主的研究有限，也尚未明确其合适的宿主。该寄生虫已在非人类灵长类动物、猪、猫、狗和老鼠中被检测到。目前尚无文献研究调查和检测该寄生虫在牛中的存在。在这项研究中，我们通过 PCR 检测了 2017 年 3 月至 2022 年 5 月期间来自 11 个不同农场的 163 头不同牛和小牛的粪便样本中是否存在脆弱双核阿米巴。对所有 PCR 阳性样本进行三色染色。使用 18S 核糖体 RNA 区域对具有预期扩增子大小的分离物进行测序，并通过 BLAST 分析确定其基因型。对序列进行分析，与文献中的最相似和参考序列进行比较，形成一个系统发育树。我们在 163 个粪便样本中的 31 个（19.01%）中检测到脆弱双核阿米巴。在 31 个阳性样本中，通过三色染色法检测到脆弱双核阿米巴包囊/滋养体。从阳性样本中选择用于分子分析的所有 PCR 产物均具有相同的核苷酸序列。BLAST 分析结果表明，所有序列均属于脆弱双核阿米巴基因型 1。这项研究首次确定牛是脆弱双核阿米巴的合适宿主。此外，我们检测到的寄生虫亚类属于基因型 1，这是人类中最常见的类型，表明该寄生虫可能具有人畜共患的特征。我们的研究结果对于寄生虫的流行病学具有重要意义，因为其传播方式存在争议，并且有关其合适宿主的可用数据有限。
