Three cases of Diphyllobothrium nihonkaiense infection in Korea.

Until 2012, a total of 48 cases of diphyllobothriasis had been reported in Korea, all of which were morphologically identified as Diphyllobothrium latum. However, some of these specimens were analyzed by nucleotide sequencing of the mitochondrial cox1 gene, which showed that all were D. nihonkaiense, not D. latum. After that, 3 further cases of diphyllobothriasis were confirmed as D. nihonkaiense. In the present study, 3 new cases of D. nihonkaiense were detected from 2011 through 2013. The hosts were infected through consumption of salmonid fishes, such as the trout or salmon, and 2 of them experienced severe diarrhea prior to proglottid passage. All of the tapeworms were confirmed to be D. nihonkaiense by genetic identification. This proved again that most diphyllobothriasis in Korea have been caused by D. nihonkaiense.