Four Additional Cases of Diphyllobothrium nihonkaiense Infection Confirmed by Analysis of COX1 Gene in Korea

Most of the diphyllobothriid tapeworms isolated from human samples in the Republic of Korea (= Korea) have been identified as Diphyllobothrium nihonkaiense by genetic analysis. This paper reports confirmation of D. nihonkaiense infections in 4 additional human samples obtained between 1995 and 2014, which were analyzed at the Department of Parasitology, Hallym University College of Medicine, Korea. Analysis of the mitochondrial cytochrome c oxidase 1 (cox1) gene revealed a 98.5-99.5% similarity with a reference D. nihonkaiense sequence in GenBank. The present report adds 4 cases of D. nihonkaiense infections to the literature, indicating that the dominant diphyllobothriid tapeworm species in Korea is D. nihonkaiense but not D. latum.

Diphyllobothrium nihonkaiense Infections in a Family

Diphyllobothrium latum and Diphyllobothrium nihonkaiense are morphologically similar to each other, and only genetic method can differentiate clearly between the 2 species. A strobila of diphyllobothriid tapeworm discharged from a 7-year-old boy was analyzed to identify the species by mitochondrial cytochrome c oxidase subunit 1 (cox1) gene sequencing. He and his family (total 4 persons) ate slices of 3 kinds of raw fish 16 days before visiting our outpatient clinic. All family members complained of abdominal pain and watery diarrhea. They all expelled tapeworm strobilae in their stools. They were treated with a single oral dose of praziquantel and then complained of no more symptoms. The cox1 gene sequencing of the strobila from the boy revealed 99.9% (687/688 bp) similarity with D. nihonkaiense and only 93.2% (641/688 bp) similarity with D. latum. Thus, we assigned this tapeworm as D. nihonkaiense. This is the first report of D. nihonkaiense infection in a family in Korea, and this report includes the 8th pediatric case in Korea. The current report is meaningful because D. nihonkaiense infection within a family is rare.

Four Additional Cases of Diphyllobothrium nihonkaiense Infection Confirmed by Analysis of COX1 Gene in Korea

Most of the diphyllobothriid tapeworms isolated from human samples in the Republic of Korea (= Korea) have been identified as Diphyllobothrium nihonkaiense by genetic analysis. This paper reports confirmation of D. nihonkaiense infections in 4 additional human samples obtained between 1995 and 2014, which were analyzed at the Department of Parasitology, Hallym University College of Medicine, Korea. Analysis of the mitochondrial cytochrome c oxidase 1 (cox1) gene revealed a 98.5-99.5% similarity with a reference D. nihonkaiense sequence in GenBank. The present report adds 4 cases of D. nihonkaiense infections to the literature, indicating that the dominant diphyllobothriid tapeworm species in Korea is D. nihonkaiense but not D. latum.

Diphyllobothrium nihonkaiense Infections in a Family

Diphyllobothrium latum and Diphyllobothrium nihonkaiense are morphologically similar to each other, and only genetic method can differentiate clearly between the 2 species. A strobila of diphyllobothriid tapeworm discharged from a 7-year-old boy was analyzed to identify the species by mitochondrial cytochrome c oxidase subunit 1 (cox1) gene sequencing. He and his family (total 4 persons) ate slices of 3 kinds of raw fish 16 days before visiting our outpatient clinic. All family members complained of abdominal pain and watery diarrhea. They all expelled tapeworm strobilae in their stools. They were treated with a single oral dose of praziquantel and then complained of no more symptoms. The cox1 gene sequencing of the strobila from the boy revealed 99.9% (687/688 bp) similarity with D. nihonkaiense and only 93.2% (641/688 bp) similarity with D. latum. Thus, we assigned this tapeworm as D. nihonkaiense. This is the first report of D. nihonkaiense infection in a family in Korea, and this report includes the 8th pediatric case in Korea. The current report is meaningful because D. nihonkaiense infection within a family is rare.

Molecular Identification of Diphyllobothrium nihonkaiense from 3 Human Cases in Heilongjiang Province with a Brief Literature Review in China

Human diphyllobothriasis is a widespread fish-borne zoonosis caused by the infection with broad tapeworms belonging to the genus Diphyllobothrium. In mainland China, so far 20 human cases of Diphyllobothrium infections have been reported, and the etiologic species were identified as D. latum and D. nihonkaiense based on morphological characteristics or molecular analysis. In the present study, proglottids of diphyllobothriid tapeworms from 3 human cases that occurred in Heilongjiang Province, China were identified as D. nihonkaiense by sequencing mitochondrial cytochrome c oxidase subunit I (cox1) and NADH dehydrogenase subunit 5 (nad5) genes. Two different cox1 gene sequences were obtained. One sequence showed 100% homology with those from humans in Japan. The remaining cox1 gene sequence and 2 different nad5 gene sequences obtained were not described previously, and might reflect endemic genetic characterizations. D. nihonkaiense might also be a major causative species of human diphyllobothriasis in China. Meanwhile, the finding of the first pediatric case of D. nihonkaiense infection in China suggests that infants infected with D. nihonkaiense should not be ignored.

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.

Extracorporeal Worm Extraction of Diphyllobothrium nihonkaiense with Amidotrizoic Acid in a Child

Infection cases of diphyllobothriid tapeworms are not much in the below teen-age group. We report a case of Diphyllobothrium nihonkaiense infection in a 13-year-old boy. He presented with severe fatigue, occasional abdominal pain at night time. He also had several episodes of tapeworm segment discharge in his stools. By his past history, he had frequently eaten raw fish including salmon and trout with his families. Numerous eggs of diphyllobothriid tapeworm were detected in the fecal examination. We introduced amidotrizoic acid as a cathartic agent through nasogastroduodenal tube and let nearly whole length (4.75 m) of D. nihonkaiense be excreted through his anus. After a single dose of praziquantel, the child's stool showed no further eggs, and his symptoms disappeared. The evacuated worm was identified as D. nihonkaiense by mitochondrial cox1 gene analysis. Here we report a successful extracorporeal worm extraction from an infection case of D. nihonkaiense by the injection of amidotrizoic acid.

Registro de nuevos casos de difilobotriasis humana en Chile (1981-1992), incluído un caso de infección múltiple por diphyllobothrium latum / Record of new cases of human diphyllobothriasis in Chile (1981-1992), including a case of multiple diphyllobotrium latum infection

New records of human diphyllobothriasis in Chile (1981-1992), with a case of multiple diphyllobotrium latum infection