Cleveland Christopher A, Eberhard Mark L, Garrett Kayla B, Thompson Alec T, Swanepoel Liandrie, Miller Elizabeth A, Stephens Odin L, Yabsley Michael J
Southeastern Cooperative Wildlife Disease Study, University of Georgia 589 D. W. Brooks Dr., Athens, Georgia 30602.
Warnell School of Forestry and Natural Resources, University of Georgia, 180 E. Green St., Athens, Georgia 30602.
J Parasitol. 2020 Oct 1;106(5):616-622. doi: 10.1645/18-178.
The prevalence and diversity of parasitic nematodes in wildlife have been well studied for certain species, yet for others considerable gaps in knowledge exist. The parasitic nematode Dracunculus insignis infects North American wildlife, and past research on this species has led to an increased understanding of the potential host diversity and transmission of the closely related human Guinea worm, Dracunculus medinensis (which is currently the focus of a global eradication program). Many definitive hosts have been documented for D. insignis; however, the life cycle has been studied only in laboratories, and only a single phylogenetic study has been conducted on D. insignis (from Canada). The goals of the present study were to investigate the prevalence of infections with Dracunculus species among wildlife at a single site (Di-Lane plantation) in the southeastern United States, evaluate the genetic diversity of parasites at this site, and investigate potential paratenic hosts that may be involved in transmission. Over 3 yr, we sampled 228 meso-mammals, reporting an overall prevalence of infection with Dracunculus insignis of 20% (46/228). Amphibians and fish were sampled in the same geographic area as infected meso-mammals. Dracunculus insignis third-stage larvae were recovered from 2 different species of amphibians, but all fish sampled were negative. Phylogenetic analysis of the partial cytochrome c oxidase I (COI) gene showed very little diversity of Dracunculus at Di-Lane; however, we did recover a single nematode from a Virginia opossum (Didelphis virginiana) that falls outside of the D. insignis clade, more closely aligns with Dracunculus lutrae, and may represent an undescribed species. This work documents the occurrence of D. insignis in frogs, a potential transmission pathway for D. insignis at a single geographic site in nature. When applied to the global Guinea Worm Eradication Program, and Chad, Africa, in particular, this work increases our knowledge of the potential role of aquatic animals in the transmission of Dracunculus species and informs on potential intervention strategies that may be applied to the eradication of Guinea worm in Africa.
对于某些物种，野生动物体内寄生线虫的流行情况和多样性已得到充分研究，但对于其他物种，仍存在相当大的知识空白。寄生线虫麦地那龙线虫感染北美野生动物，过去对该物种的研究增进了人们对与其密切相关的人类几内亚龙线虫（目前是全球根除计划的重点）潜在宿主多样性和传播途径的了解。已记录到许多麦地那龙线虫的终末宿主；然而，其生命周期仅在实验室中进行过研究，且仅对来自加拿大的麦地那龙线虫进行过一项系统发育研究。本研究的目的是调查美国东南部一个地点（迪莱恩种植园）野生动物中麦地那龙线虫属感染的流行情况，评估该地点寄生虫的遗传多样性，并调查可能参与传播的潜在转续宿主。在3年多的时间里，我们对228只中型哺乳动物进行了采样，报告显示麦地那龙线虫的总体感染率为20%（46/228）。在与感染中型哺乳动物相同的地理区域对两栖动物和鱼类进行了采样。从2种不同的两栖动物中分离出了麦地那龙线虫的第三期幼虫，但所有采样的鱼类均为阴性。对细胞色素c氧化酶I（COI）基因部分序列的系统发育分析表明，迪莱恩的麦地那龙线虫多样性极低；然而，我们确实从一只弗吉尼亚负鼠（北美负鼠）体内分离出一条线虫，它不属于麦地那龙线虫分支，与水獭龙线虫的亲缘关系更近，可能代表一个未描述的物种。这项工作记录了麦地那龙线虫在青蛙体内的存在情况，这是自然界中一个地理地点上麦地那龙线虫的一种潜在传播途径。当应用于全球几内亚龙线虫根除计划，特别是非洲的乍得时，这项工作增加了我们对水生动物在麦地那龙线虫属传播中潜在作用的认识，并为可能应用于非洲几内亚龙线虫根除的潜在干预策略提供了信息。
