Adults live in the lungs of mammals, usually encapsulated by a granuloma. Eggs are laid and many are trapped in the lung tissue, but some enter the air passages, are carried up the trachea and are swallowed. If deposited in water, the eggs will develop and a miracidium will hatch. The miracidium will infect freshwater snails Within the snail, development proceeds through mother sporocyst, mother redia and daughter redia stages. Cercariae armed with an oral style are produced and released. These cercariae have a short tail and crawl on the bottom until they contact a crab or crayfish. Then they penetrate the soft inter-segmental membranes with the aid of their stylet and migrate to the heart, where they encyst as a metacercaria. When the infected crustacean is eaten by a suitable mammal, the metacercariae excyst and penetrate the intestine, ending up in the abdominal cavity. They migrate to the diaphragm, through it into the pleural cavity, and then into lung tissue. The juvenile worms usually pair up and a capsule forms around them. This is a lengthy life cycle, with egg development taking a few weeks, development in the snail a few months, development in the crustacean over 1 month, and development to sexual maturity in the definitive host about 5-6 months.