Otterly diverse - A high diversity of species (Spirurida: Dracunculoidea) in North American river otters ().

The genus contains numerous species of subcutaneous parasites of mammals and reptiles. In North America, there are at least three mammal-infecting species of . Reports of infections have been reported from river otters () since the early 1900s; however, little is known about the species infecting otters or their ecology. Most reports of do not have a definitive species identified because females, the most common sex found due to their larger size and location in the extremities of the host, lack distinguishing morphological characteristics, and few studies have used molecular methods to confirm identifications. Thus, outside of Ontario, Canada, where both and have been confirmed in otters, the species of in river otters is unknown. In the current study, molecular characterization of nematodes from river otters revealed a high diversity of species. In addition to confirming infections, two new clades were detected. One clade was a novel species in any host and the other was a clade previously detected in Virginia opossums () from the USA and a domestic dog from Spain. No infections with were detected and neither new lineage was genetically similar to , which was recently described from a neotropical otter () from Argentina. These data also indicate that spp. infections in otters are widespread throughout Eastern North America. Currently the life cycles for most of the spp. infecting otters are unknown. Studies on the diversity, life cycle, and natural history of Dracunculidae parasites in wildlife are important because the related parasite, (human Guinea worm) is the subject of an international eradication campaign and there are increasing reports of these parasites in new geographic locations and new hosts, including new species in humans and domestic dogs.