Parasite
Paragonimus westermani
Lung fluke from undercooked crab
par-uh-GON-ih-mus wes-ter-MAH-nye
High-yield clue
Undercooked crab/crayfish transmission with adults in the lung produces chronic cough and operculated eggs found in sputum.
Overview
The oriental lung fluke acquired from raw or undercooked freshwater crabs and crayfish, whose adults reside in the lungs, a classic study model for a pulmonary trematode.
Classification
- Trematode (fluke)
- Adults encapsulated in lung tissue
- Snail first host, crab/crayfish second host
- Operculated eggs
Lab & identification clues
- Operculated eggs identified in sputum (or stool)
- Chronic cough with blood-tinged sputum vocabulary
- Chest imaging concepts
Associations
- Raw/undercooked freshwater crab or crayfish
- Pulmonary paragonimiasis vocabulary
- May mimic chronic respiratory illness (study caution)
- East/Southeast Asian distribution
Commonly confused with
- Clonorchis sinensis
- Fasciola hepatica
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.