Yue Chanjuan, Yang Wanjing, Qi Dunwu, Yang Mei, Ayala James Edward, Zhou Yanshan, Chen Chao, Su Xiaoyan, Hou Rong, Liu Songrui
The Conservation of Endangered Wildlife Key Laboratory of Sichuan Province, Chengdu Research Base of Giant Panda Breeding, 1375 Panda Road, Chenghua District, Chengdu 610081, China.
Pathogens. 2025 Aug 6;14(8):783. doi: 10.3390/pathogens14080783.
() is a predominantly free-living nematode commonly found in sewage systems and decomposing organic matter. While primarily saprophytic, it has been documented as an opportunistic pathogen in human urinary and gastrointestinal tracts. The Chinese red panda (), a rare and protected species in China, has not previously been reported as a host for spp. infections. This study reports the first documented occurrence of R. axei in red panda feces, unambiguously confirmed through integrative taxonomic approaches combining morphological and molecular analyses. The nematodes exhibited key morphological features consistent with , including a cylindrical rhabditiform esophagus, sexually dimorphic tail structures, and diagnostic spicule morphology. Molecular analysis based on 18S-ITS-28S rDNA sequencing confirmed their identity, showing >99% sequence similarity to reference strains (GenBank: PP135624.1, PP135622.1). Phylogenetic reconstruction using 18S rDNA and ITS rDNA sequences placed the isolate within a well-supported clade, clearly distinguishing it from related species such as and . The findings demonstrate the ecological plasticity of as a facultative parasite capable of infecting non-traditional hosts and further highlight potential zoonotic risks associated with environmental exposure in captive wildlife populations. Our results emphasize the indispensable role of molecular diagnostics in accurately distinguishing morphologically similar nematodes within the Rhabditidae family, while providing essential baseline data for health monitoring in both in situ and ex situ conservation programs for this endangered species.
（某种线虫）是一种主要营自由生活的线虫，常见于污水系统和分解的有机物质中。虽然它主要是腐生的，但已有文献记载它是人类泌尿生殖道和胃肠道中的机会性病原体。中国小熊猫（某种熊猫）是中国的珍稀保护物种，此前尚未有报道称其为该线虫属感染的宿主。本研究报告了首次在小熊猫粪便中记录到艾氏类圆线虫，通过结合形态学和分子分析的综合分类学方法明确证实。这些线虫呈现出与艾氏类圆线虫一致的关键形态特征，包括圆柱形的杆状食道、两性异形的尾部结构以及具有诊断性的交合刺形态。基于18S - ITS - 28S rDNA测序的分子分析证实了它们的身份，显示与参考菌株（GenBank：PP135624.1，PP135622.1）的序列相似性>99%。使用18S rDNA和ITS rDNA序列进行的系统发育重建将该分离株置于一个得到充分支持的艾氏类圆线虫分支内，明显将其与诸如其他相关物种区分开来。这些发现证明了艾氏类圆线虫作为一种兼性寄生虫能够感染非传统宿主的生态可塑性，并进一步凸显了圈养野生动物种群中与环境暴露相关的潜在人畜共患病风险。我们的结果强调了分子诊断在准确区分杆线虫科内形态相似的线虫方面不可或缺的作用，同时为该濒危物种的原地和迁地保护计划中的健康监测提供了重要的基线数据。
