Animal Systematics and Ecology Speciality Research Unit, Department of Zoology, Faculty of Science, Kasetsart University, Bang Khen Campus, Bangkok, 10900, Thailand.
Parasite. 2019;26:47. doi: 10.1051/parasite/2019047. Epub 2019 Jul 30.
Trichodinids, which are ciliate protists, are causative agents of an aquatic animal disease, trichodiniasis, especially among both captive and wild fish. This disease can adversely affect aquaculture and have economic impacts. The objectives of this study were to evaluate the prevalence and mean intensity of Trichodina unionis infection, describe qualitative and quantitative morphological characters, and perform a molecular phylogenetic analysis. The gastropod samples were randomly collected by hand-picking and a hand net. Trichodina unionis was collected by the crushing method under a stereomicroscope. Among all 4977 examined gastropods, 55 individuals of two gastropod species, Gyraulus siamensis and Physella acuta, were found to be infected by T. unionis, with overall prevalence and mean intensity of infection of 1.11% and 16.65, respectively. The characteristics of the denticles indicated T. unionis as having moderately wide blades and moderately curved blade margins, with distinctive bend angles near the distal end. The quantitative characters showed some variations, which could be due to food availability. Molecular phylogenetic analysis conducted with 18S rRNA provided a monophyletic tree of our specimens and previously identified T. unionis, confirming species identification. This study represents the first record of T. unionis in Thailand.
纤毛虫 Trichodinids 是引起水生动物疾病——纤毛虫病的病原体，特别是在养殖和野生鱼类中。这种疾病会对水产养殖业产生不利影响，并造成经济影响。本研究的目的是评估 Trichodina unionis 感染的流行率和平均强度，描述定性和定量形态特征，并进行分子系统发育分析。采用手挑和手抄网的方式随机采集腹足类样本，在体视显微镜下用压碎法采集 Trichodina unionis。在检查的 4977 只腹足类中，发现两种腹足类（暹罗圆田螺和尖膀胱螺）的 55 只个体感染了 T. unionis，总感染率和平均感染强度分别为 1.11%和 16.65。齿的特征表明 T. unionis 具有中等宽度的叶片和中等弯曲的叶片边缘，在末端附近具有明显的弯曲角度。定量特征显示出一些变化，这可能是由于食物供应的变化。使用 18S rRNA 进行的分子系统发育分析为我们的标本和先前鉴定的 T. unionis 提供了一个单系树，证实了物种鉴定。本研究代表了泰国首次记录到 T. unionis。
