In Asia, classical paragonimiasis is caused by P westermani and P heterotremus adult flukes and their eggs. The adult flukes of P westermani are up to 12 mm long and 7 mm wide and occur throughout the Far East. A triploid parthenogenetic form of P westermani , which is larger, produces more eggs and elicits greater disease, has been described in Japan, Korea, Taiwan, and parts of eastern China. P heterotremus occurs in Southeast Asia and adjacent parts of China. Extrapulmonary paragonimiasis is caused by larval stages of Paragonimus skrjabini and Paragonimus miyazakii . The worms rarely mature. P skrjabini occurs in China, and P miyazakii occurs in Japan. African forms causing extrapulmonary paragonimiasis include Paragonimus africanus (Nigeria, Cameroon) and Paragonimus uterobilateralis (Liberia, Guinea, Nigeria, Gabon). Paragonimus mexicanus and Paragonimus ecuadoriensis occur in Mexico, Costa Rica, Ecuador, and Peru. Paragonimus kellicotti , a lung fluke of mink and opossums in the United States, also can cause a zoonotic infection in humans.