Paragonimiasis is a lung fluke (parasitic flatworm) which infects man by ingestion of raw crabs or crayfish. The most common symptoms relate to a lung infection and begin with a low-grade fever and cough, dry at first, followed by a productive cough with blood-flecked sputum. The infection becomes chronic and progresses slowly. Shortness of breath, weakness, lack of energy and weight loss appear. Those persons with mild infections do not have any symptoms at all.
This disease occurs throughout the Far East, in West Africa, South Asia, Indonesia, New Guinea, Central America and northern South America.
In Japan, paragonimiasis caused by Paragonimus including P. westermani and P. miyazakii is often misdiagnosed as a lung cancer or tuberculosis. The worm occasionally invaded in brain, and caused cerebral paragonimiasis.