Gastrointestinal Parasites and Bacteria in Free-Living South American Sea Lions (Otaria flavescens) in Chilean Comau Fjord and New Host Record of a Diphyllobothrium scoticum-Like Cestode

Abstract

Present study aimed to characterize gastrointestinal parasites and culturable bacteria from free-living South American sea lions (Otaria flavescens) inhabiting waters of Comau Fjord, Patagonia, Chile. Therefore, a total of 28 individual fecal samples were collected from sea lions within their natural marine habitat during several diving expeditions. Using classical parasitological techniques, study revealed infections with five different gastrointestinal parasite genera. In addition, bacterial cultures showed presence of at least 28 different bacterial genera. Referring to parasites, protozoan, and metazoan species were found with some of them bearing anthropozoonotic potential and/or pathogenic impact for these marine mammals. As such, four of identified parasite genera harbored zoonotic potential (i.e., Entamoeba, Balantidium, Diphyllobothrium, Anisakis) and one genus (Parafilaroides) represented a specific lungworm of marine pinnipeds. Proglottids from fecal samples showed high morphological homology to "Diphyllobothrium" scoticum (Rennie and Reid, 1912; Meggitt, 1924), which was found in Antarctic sea leopards (Hydrurga leptonyx; Phocidae), but contained eggs of smaller size. Molecular characterization revealed 97-100% identity to a new "Diphyllobothrium" species which was recently isolated from a Californian sea lion (Zalophus californianus; Otariidae) in San Francisco. As such, O. flavescens represents a new host record for this parasite species. Furthermore, potential zoonotic bacteria (i.e., Clostridium, Escherichia, Vibrio, Yersinia, Salmonella) were identified amongst others in O. flavescens indicating a reservoir role for these pinnipeds in marine ecosystem. Current data should be considered as a baseline study for future monitoring surveys on anthropozoonotic pathogens circulating in wild free-living sea lions and their possible impact on public health issues and marine wildlife.

Diphyllobothrium sprakeri n. sp. (Cestoda: Diphyllobothriidae): a hidden broad tapeworm from sea lions off North and South America

“…Synonyms : Diphyllobothrium sp. 1 of Waeschenbach et al [ 4 ], Hermosilla et al [ 24 ] and Kuzmina et al [ 18 ]…”

“…Recently, Hermosilla et al [ 24 ] collected two headless tapeworms from fecal samples of SASLs in Chile and considered them a ‘ Diphyllobothrium scoticum -like cestode.’ The morphological description of these tapeworms by Hermosilla et al [ 24 ] is incomplete; however, they are similar to D. sprakeri n. sp. in having a thick-walled sac-like structure in the terminal part of the uterus, longitudinal muscle layer wide (51–100 vs 100) and egg size (54–61 × 38–44 vs 59–75 × 40–47).…”

“…However, the evaluation Baylis’ [ 21 ] material by Baer et al [ 23 ] and Hernández-Orts et al [ 2 ] suggested that these specimens belong to A. pacificus . Hermosilla et al [ 24 ] reported a ‘ Diphyllobothrium scoticum -like cestode’ from SASLs from the Pacific coast of Chile to be molecularly conspecific with samples from CSLs. The recent revision of metazoan parasites of SASL by Ebmer et al [ 25 ] reported 44 metazoan taxa (only 25 were identified to the species level), including A. pacificus with its synonyms, Clistobothrium delphini (Bosc, 1802) [as Phyllobothrium delphini (Bosc, 1802)] and unidentified species of Anophryocephalus Baylis, 1922 and ' Diphyllobothrium '.…”

“…The main goal of this article is the description of a new species previously reported as ‘ Diphyllobothrium ’ sp. 1 by Waeschenbach et al [ 4 ], Hermosilla et al [ 24 ] and Kuzmina et al [ 18 ] on the basis of detailed morphological and molecular data.…”

Antarctophthirus microchir infestation in synanthropic South American sea lion (Otaria flavescens) males diagnosed by a novel non-invasive method

“…Consequently, the sampling process delivers a smaller amount of biological material and is more time consuming than examination of fixed animals (Leonardi 2014 ) or during necropsies. However, in today’s world, where anthropogenic pressure influences and determines wildlife as intensive as never before, non-invasive or minimally invasive methods should constitute indispensable tools in research of marine mammals (Gales et al 2009 ), and it is in our responsibility to develop creative, protecting methods for obtaining a broad range of biological material (Kleinertz et al 2014 ; Hermosilla et al 2015 , 2016a , b , 2018a , b ).…”