Since late 1970s, the southern Chilean city Valdivia constitutes home for a unique bachelor group of South American sea lions (Otaria flavescens), initially descendant from colonies at the Pacific coast, but now directly living in a freshwater habitat in close proximity to human population and a vast amount of wild and domestic animal species. In the framework of a parasitological monitoring program, 115 individual fecal samples were collected from synanthropic South American sea lions between March and May 2018. For comparative reasons, 79 individual fecal samples from two free-living O. flavescens colonies at the Pacific coast were also sampled. Coproscopical analyses revealed the presence of nine different parasite taxa in individual fecal samples, including two protozoan (Cryptosporidium spp. and Giardia spp.) and seven metazoan parasites (Anisakidae gen. spp., Diphyllobothriidae gen. spp., Ogmogaster heptalineatus, Trematoda indet. type 1, Trematoda indet. type 2, Otostrongylus circumlitus, and Parafilaroides spp.), and morphological and molecular characterizations of adult helminths confirmed identification of following species: Anisakis simplex/A. pegreffi, Pseudoterranova cattani, Contracaecum ogmorhini, and Adenocephalus pacificus. For the first time, the results of the current study show the presence of zoonotic relevant Giardia- and Cryptosporidium-infections in two free-ranging colonies of South American sea lions apart from human settlement. Furthermore, a detailed literature search of previous publications on the endoparasite fauna of South American sea lions was conducted, revealing reports of at least 50 protozoan and metazoan parasite taxa including findings of the current study. Thereby, at least 25 of reported taxa (50%) have been recorded to bear zoonotic potential. The present study illustrates a successful application of non-invasive screening methods and their applicability in the field of marine mammal parasitology, bringing new insights into the endogenous parasite fauna of South American sea lions in Southern Chile, including anthropozoonotic protozoan and metazoan taxa.

中文翻译：

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在南美海狮（Otaria flavescens）的同种人类和太平洋殖民地中循环的人类寄生虫：非侵入性技术数据和文献回顾

自 1970 年代后期以来，智利南部城市瓦尔迪维亚是一群独特的南美海狮 (Otaria flavescens) 的家园，它们最初是太平洋沿岸殖民地的后裔，但现在直接生活在靠近人类种群和大量的野生和家养动物物种。在寄生虫学监测计划的框架内，在 2018 年 3 月至 5 月期间从同人类共生的南美海狮收集了 115 个个体粪便样本。出于比较原因，来自太平洋沿岸两个自由生活的 O. flavescens 殖民地的 79 个个体粪便样本也采样。粪检分析显示，个体粪便样本中存在九种不同的寄生虫分类群，包括两种原生动物（隐孢子虫属和贾第鞭毛虫属）。) 和七种后生寄生虫（异尖线虫属、双叶丝虫属、Ogmogaster heptalineatus、吸虫属 indet. 1 型、吸虫属 indet. 2 型、耳圆线虫属和 Parafilaroides spp. 成虫的分子形态特征），以及确认鉴定了以下物种：Anisakis simplex/A。pegreffi、Pseudoterranova cattani、Contracaecum ogmorhini 和 Adenocephalus pacificus。目前的研究结果首次表明，除了人类定居点外，南美海狮的两个自由放养群落中存在与人畜共患相关的贾第虫和隐孢子虫感染。此外，还对以前关于南美海狮体内寄生虫群的出版物进行了详细的文献检索，揭示至少 50 种原生动物和后生动物寄生虫分类群的报告，包括当前研究的结果。因此，至少有 25 个已报告的分类群 (50%) 被记录为具有人畜共患的潜力。本研究说明了非侵入性筛查方法的成功应用及其在海洋哺乳动物寄生虫学领域的适用性，为智利南部南美海狮的内源性寄生虫动物群带来了新的见解，包括人类原生动物和后生动物分类群。