Parasite
Clonorchis sinensis
Chinese liver fluke from raw freshwater fish
kloh-NOR-kis sih-NEN-sis
High-yield clue
Raw freshwater fish transmission, adults living in the bile ducts, and a chronic link to cholangiocarcinoma are the core clues.
Overview
The Chinese/oriental liver fluke acquired from raw or undercooked freshwater fish, a classic study model for bile-duct trematode infection and its cancer association.
Classification
- Trematode (fluke)
- Adults reside in bile ducts
- Snail first host, freshwater fish second host
- Small operculated eggs
Lab & identification clues
- Small operculated eggs with shoulder/knob vocabulary
- Eggs identified on stool examination
- Biliary imaging concepts
Associations
- Raw/undercooked freshwater fish consumption
- Biliary obstruction and cholangitis vocabulary
- Chronic infection linked to cholangiocarcinoma
- East/Southeast Asia distribution
Commonly confused with
- Fasciola hepatica
- Paragonimus westermani
Your notes
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.