The life cycle of Paragonimus kellicotti in cats.

Migration and development of Paragonimus kellicotti were studied in cats killed between 1 and 265 days after feeding 15--20 metacercariae from the hearts of naturally infected crayfish. Metacercariae excysted in the intestine and appeared in the peritoneal cavity within 24 hr. Some young flukes penetrated the diaphragm and migrated to the pleural cavity during the first week, but the majority penetrated the pleura between 10 and 14 days. No flukes were found in the pleural cavity after 23 days postinfection. By 4 weeks postinfection, the flukes were well established within lung parenchyma, mainly in the right caudal lobe, where most of their growth occurred. Eggs first were seen in flukes on the 34th day postinfection and in feces 2 days later. Estimated daily ova production ranged from 1,000 to 2,000 eggs/fluke/day.