a helminthosis of carnivores, swine, and humans that affects primarily the lungs. The infection is encountered in China, Korea, and Japan but is rare in the USSR. The causative agent in humans is the lung fluke Paragonimus ringeri, which parasitizes the lungs and sometimes the brain and other organs. The eggs of the helminth are discharged in the sputum and feces of an infected person. Larvae develop in the eggs in open water, shed their egg membrane, and enter snails, where caudate larvae—cercaria—are formed. The caudate larvae go out into the water and embed themselves in freshwater crustaceans.

Paragonimiasis is acquired by eating raw crustaceans infected with the larvae of the helminth. Treatment is with bithionol. Preventive measures include adequate cooking of crustaceans used as food and protection of waters from contamination.