biostudies-literatureUnknown61(6)Ishizaki YAlthough trichuriasis, a zoonotic disease, has recently become rare in Japan due to improved environmental hygiene, we herein report a 79-year-old man in whom a worm was incidentally found in the ascending colon during colonoscopy for positive fecal occult blood and was endoscopically removed. A genetic analysis identified the worm as Trichuris trichiura possessing mixed sequences from non-human primate and human origins. Despite controversy regarding Trichuris trichiura infection originating from Japanese macaques, according to some studies, it originates primarily from humans. This report suggests the efficacy of a genetic analysis for identifying infection sources.Internal medicine (Tokyo, Japan)821-825https://www.ebi.ac.uk/biostudies/studies/S-EPMC8987263biostudies-literatureTrichuris trichiura Incidentally Detected by Colonoscopy and Identified by a Genetic Analysis.PMC8987263Onizawa MIshizaki YKawashima KOhira HHasegawa MGunji NHikichi TfalseTrichuris trichiura Incidentally Detected by Colonoscopy and Identified by a Genetic Analysis.Although trichuriasis, a zoonotic disease, has recently become rare in Japan due to improved environmental hygiene, we herein report a 79-year-old man in whom a worm was incidentally found in the ascending colon during colonoscopy for positive fecal occult blood and was endoscopically removed. A genetic analysis identified the worm as Trichuris trichiura possessing mixed sequences from non-human primate and human origins. Despite controversy regarding Trichuris trichiura infection originating from Japanese macaques, according to some studies, it originates primarily from humans. This report suggests the efficacy of a genetic analysis for identifying infection sources.2022-01-01T00:00:00Z2022 Mar2025-04-22T09:48:48.404Z2025-04-05T23:16:10.778ZS-EPMC89872633447102910.2169/internalmedicine.8012-21