Abstract: Objective　To identify the species of trematodes isolated from laying ducks in Nanchang City using morphological and molecular approaches. Methods　Trematodes were isolated from the hepatobiliary duct, gallbladder and large intestine of market⁃sold laying ducks in Nanchang City. Following morphological characterization, total DNA was extracted from all trematode specimens, and internal transcribed spacer region (ITS) and cytochrome C oxidase subunit 1 (Cox1) genes were amplified using PCR assay and sequenced. Sequence alignment was performed using the Blast software, and homology and phylogenetic analyses were done in the trematode isolates based on ITS and Cox1 gene sequences. Results　The morphological characteristics of two trematode isolates from the large intestine of laying ducks were similar to those of Echinostoma revolutum and E. miyagawai, and the morphological characteristics of eight trematode samples isolated from the hepatobiliary duct and gallbladder of laying ducks were similar to those of Amphimerus anatis. The ITS and Cox1 gene sequences of the two trematode isolates from the large intestine of laying ducks had 99.3% and 98.9%-99.4% homology with E. miyagawai, and the phylogenetic analysis showed that two trematode isolates had the closest genetic relationship with E. miyagawai based on ITS and Cox1 gene sequences. The ITS gene sequences of eight trematode isolates from the hepatobiliary duct and gallbladder of laying ducks shared 95.1%-95.5% with Opisthorchis sudarikovi and Clonorchis sinensis, while the Cox1 gene sequences of eight trematode isolates from the hepatobiliary duct and gallbladder of laying ducks shared 86.3%-86.4% and 85.5%-85.7% with O. viverrini and O. sudarikovi. ITS gene sequence⁃based phylogenetic analysis showed that the duck⁃derived trematode isolates had the closest genetic relationship with C. sinensis, and Cox1 gene sequence⁃based phylogenetic analysis showed that the duck⁃derived trematode isolates had the closest genetic relationship with Metorchis orientalis and O. viverrini. Conclusions　The trematode isolates from the large intestine of laying ducts in Nanchang City may be E. miyagawai, and the trematode isolates from the hepatobiliary duct and gallbladder may be an unidentified trematode species of the family Opisthorchiidae.

Key words: Trematode, Laying duck, Morphological feature, Molecular identification, Internal transcribed spacer region, Cytochrome C oxidase subunit 1, Nanchang City

摘要： 目的　对分离自南昌市蛋鸭体内的吸虫进行形态学和分子生物学鉴定。方法　从南昌市市售蛋鸭肝胆管、胆囊和大肠中分离吸虫。经形态学鉴定后，提取所有吸虫样本总DNA，PCR扩增内转录间隔区（ITS）和细胞色素氧化酶亚基Ⅰ（Cox1）基因并测序，序列经Blast比对后，分别对吸虫样本ITS和Cox1基因进行同源性和系统发育分析。结果　2条分离自蛋鸭大肠的吸虫样本与卷棘口吸虫和宫川棘口吸虫形态特征相似，8条分离自蛋鸭肝胆管和胆囊的吸虫样本形态与对体吸虫相似。2条分离自蛋鸭大肠的吸虫样本ITS和Cox1基因序列与宫川棘口吸虫同源性分别为99.3%和98.9%～99.4%，基于ITS和Cox1基因序列的系统进化树显示吸虫样本与宫川棘口吸虫亲缘关系最近。8条分离自蛋鸭肝胆管和胆囊吸虫样本ITS基因序列与苏氏肝居吸虫和华支睾吸虫同源性分别为95.1%～95.5%，Cox1基因序列与麝后睾吸虫和苏氏肝居吸虫同源性分别为86.3%～86.4%和85.5%～85.7%。基于ITS和Cox1基因序列的系统进化树显示，吸虫样本ITS基因序列与华支睾吸虫亲缘关系最近，Cox1基因序列与东方次睾吸虫和麝后睾吸虫亲缘关系最近。 结论　自南昌市蛋鸭大肠分离的吸虫可能为宫川棘口吸虫，分离自蛋鸭肝胆管和胆囊的吸虫可能为一种未定种属的后睾科吸虫。

关键词: 吸虫, 蛋鸭, 形态特征, 分子鉴定, 内转录间隔区, 细胞色素氧化酶亚基Ⅰ, 南昌市