关键词: 毛首线虫, 种类鉴定, 形态学分析, 内转录间隔区1

Abstract: Objective To investigate the morphological characteristics of Trichuris sp. from giraffe in Hefei wild zoo and identify its species using molecular techniques. Methods Morphological characteristics of Trichuris collected from giraffe were analyzed. The internal transcribed spacer 1（ITS-1） was amplified by PCR and the PCR product was sequenced. The resulting sequence was homology analysis in GenBank and its heredity evolution tree was constructed by MEGA 4.0 software. Results The male worms had a body length of 35.89-58.56 mm, an esophagus to body length ration of 0.29-0.40, and a spicule length of 1.96-3.89 mm. The thick and thin proportions of body were 7.02-23.45 mm and 28.05-40.05 mm respectively. These data showed different degrees of variation with previous reports. The PCR resulted in a product of 491 bp, comprising part of 18S rRNA and full length ITS-1. Sequence alignment showed that the identified Trichuris was most homologous（98.6%） with T. bos taurus HE608848, T. capreolus JX218218, and T. japanese AB367795, but it was only 46.0% homologous with T. discolor AB367794. In the heredity evolution tree, it was not located on the same branch as T. discolor, T. ovis and T. bos taurus. Conclusions The Trichuris sp. collected from giraffe is different from previous reports in morphology and ITS-1 sequence. Further research is needed to determine if it is a new species.

Key words: Trichuris, Species identification, Morphology analysis, Internal transcribed spacer 1