Parasite fauna of wild Antillean manatees (Trichechus manatus manatus) of the Andean Region, Colombia

Occurrence of Chiorchis fabaceus (Trematoda: Cladorchiidae) in a wild Antillean manatee (Trichechus manatus manatus): New parasitological data for this imperilled sirenian

Parasites impact wildlife populations and ecosystem health, thereby demanding regular monitoring. As part of the national conservation effort to preserve the free-ranging sirenians in Colombia, a parasitological survey was conducted between 2011 and 2023 on naturally deceased Antillean manatees (Trichechus manatus manatus). A total of 17 stranded carcasses were analysed for the occurrence of parasites. Herein, trematode adult stages were recovered from the stomach, small intestine, caecum and colon of an adult male manatee and microscopically analysed. Additionally, molecular analysis was conducted based on an almost complete coding sequence of the ITS1-5.8S-ITS2, partial sequence of 18S and 28S ribosomal DNA (rDNA) genes. Phylogenetic analysis clustered the trematode sequences within Chiorchis fabaceus species, thus constituting the first adult-based sequences isolated for the species. Presented data contribute to a better understanding of the sirenian parasite diversity.

Endoparasite survey in Amazonian manatees (Trichechus inunguis) under rehabilitation in the Peruvian Amazon

Manatee populations are declining worldwide, and all currently existing species are considered vulnerable by the IUCN. The most common problems during nurturing young Amazonian manatees, Trichechus inunguis, in rescue centres are of gastrointestinal nature leading to inappetence, diarrhoea, cachexia and even death. Endoparasites play an important role in the well-being of wildlife in captivity as well as in the wild, though information about relevant protozoan and metazoan endoparasites in Amazonian manatees is still scarce. Therefore, this study aimed to find endoparasites in T. inunguis by analyzing faecal samples from 23 Amazonian manatees which were kept in rescue centres in the Peruvian Amazon. The samples were screened for protozoan and metazoan parasites using coproscopical analysis and molecular tools. Out of twenty juvenile animals eleven were positive for at least one Eimeriidae. Two morphologically different, not yet genetically described Eimeria species were identified. One of them seems to be Eimeria trichechi which has only been described once in 1984 in Amazonian manatees from Brazil. It was not found to lead to clinical symptoms of coccidiosis in this study. The second, Eimeria sp. Type B was associated with clinical coccidiosis in a young Amazonian manatee, which showed gastrointestinal symptoms including diarrhoea, inappetence and cachexia. No other protozoan or metazoan parasite were detected in any of the samples. The present study is the first to investigate endoparasites in Amazonian manatees using molecular tools and is the first to identify an Eimeria species that could be associated with clinical symptoms in T. inunguis. With information from our study rescue centres can improve monitoring of parasites more effectively to reduce morbidity and mortality rates among rehabilitated manatees as well as improve the health status and fitness of animals for a successful release back into the wild.

First molecular identification of the trematode Pulmonicola cochleotrema (Platyhelminthes: Opisthotrematidae) in West Indian manatees (Trichechus manatus, Sirenia: Trichechidae) from Puerto Rico and Florida

West Indian manatees (Trichechus manatus) harbor a variety of endoparasites, including the nasal trematode Pulmonicola cochleotrema, which infects the respiratory tract, especially the nasal passages. Previous studies have described and identified this digenean using morphological data only. This study presents the first molecular identification of P. cochleotrema in West Indian manatees from Puerto Rico and Florida. Samples of the trematode were collected from seven manatees found stranded dead at both locations. The small subunit ribosomal DNA (18S rDNA) was amplified from each sample using universal primers for different regions of the gene, resulting in a consensus sequence of 1871 base pairs. The phylogenetic reconstruction was carried out using DNA sequences of other species of digenean parasites from other hosts, including a trematode of the same taxonomic family from another sirenian species. Specimens collected from both locations show the same molecular identity using SSU rDNA sequence data. The identity of P. cochleotrema was confirmed using the Basic Local Alignment Search Tool from the National Center for Biotechnology Information database, yielding a high similarity of 98.8 % with Opisthotrema dujonis and 98.2 % with Lankatrema mannarense located in the same clade in our analysis. The latter two digeneans belong to the Opisthotrematidae as does P. cochleotrema and previous studies reported them infecting the Eustachian tubes, esophagus, and digestive tract in dugongs (Dugong dugon). These findings evidence that the nasal trematode of manatees in Florida and Puerto Rico and the dugong, all inhabiting and feeding in marine environments, will have a marine mollusk as an intermediate host, probably a gastropod. The question remains, which species of nasal trematode are harbored by lotic-dwelling manatees in other parts of their distribution like South America.