Infection with fully mature Corynosoma cf. validum causes ulcers in the human small intestine

Abstract

Corynosoma is a parasite that can normally be found in the intestinal tract of fish-eating mammals, particularly in seals and birds. The present case proposed that Corynosoma could attain full maturity in the human intestine. A 70-year-old female complained of abdominal pain. A computed tomography (CT) scan revealed a swelling of the intraperitoneal lymph nodes with no responsible lesion. Video capsule endoscopy and double-balloon endoscopy detected several ulcerations and one parasite in the ileum, which was tightly attached at the bottom of the ulcerations. The parasite was cylindrical and measured approximately 10 mm (long) x 3 mm (wide). Pathologically, the worm had a four-layered body wall and contained embryonated eggs. The sequences of the parasite-derived nuclear ribosomal DNA fragment and mitochondrial DNA fragment of cox1 were almost identical to those of Corynosoma validum. The patient's abdominal pain immediately improved after the administration of pyrantel pamoate (1,500 mg). Corynosoma was possibly the responsible disease in a patient who complained of abdominal pain and in whom no responsible lesion was detected by CT, gastroduodenoscopy or colonoscopy. Examinations of the small intestines should be aggressively performed in such cases.

A review on fish‐borne zoonotic parasites in Iran

“…However, recent reports of human corynosomiasis from Japan showed that intestinal adults can reach sexual maturity (i.e. laying eggs), suggesting humans to be a suitable final host (Fujita et al., 2016 ; Takahashi et al., 2016 ). The species composition of Corynosoma in fish varies according to sea areas with C. strumosum tending to be the primary species (Sinisalo & Valtonen, 2003 ).…”

An annotated checklist of the eukaryotic parasites of humans, exclusive of fungi and algae

“…Route of infection. Ingestion of cystacanths in infected fish paratenic host ( Takahashi et al 2016 ).…”

“…The single case was reported from Japan as Corynosoma cf. validum based on DNA sequencing ( Takahashi et al 2016 ).…”

Neglected rare human parasitic infections: Part III: Acanthocephaliasis

“…Many acanthocephalan species are known to have low host specificity but fortunately, for ecological reasons, are not likely to be ingested by man [11] . Man was reported to be infected with at least nine acanthocephalan species, among them, Macracanthorhynchus hirudinaceus and Moniliformis moniliformis are the most common species [12,13] . Most reported cases of acanthocephaliasis have involved the gastrointestinal tract.…”