The genus Paragonimus has undergone considerable taxonomic splitting over the past 40 years.  Paragonimus westermani is the most common and widely distributed of the species.  Members of the genus are all lung flukes.  The egg capsules make their egress from the body through sputum or feces.  If the eggs are deposited in freshwater, after 16 days to several weeks of embryonation, the miracidia emerge seeking a snail of the family Thieridae, such as Semisulcospira libertina.  Once the miracidium has penetrated the snail, it sheds its ciliated epidermis and transforms into a sporocyst.  The sporocyst in turn gives rise to rediae which produce numerous cercariae.  The microcercous cercariae are characterized by their tail which is reduced to a small button at the posterior end.  The cercariae "inch" over wet rocks where they encounter and actively penetrate 11 or more species of crabs.  The cercariae encyst in the crustacean's flesh as metacercariae.  A wide range of carnivores serve as definitive or final hosts.  Humans may also be infected when they eat raw or poorly cooked crabs.  In Southeast Asia, a delicacy is known as "drunken crab".  Crabs are marinated overnight in wine which coagulates the protein and adds flavor.  Still, the metacercariae are unharmed and lead to infections.  When metacercariae are ingested, they excyst in the duodenum, eventually making their way through the wall of the intestine, diaphragm and lung pleural to the spaces of the lungs.