Life cycle No intermediate host is necessary Larva takes a free living mode The filariform larva is the infective stage Infection routes: skin penetration(mainly): orally swallow: maternal-child Residing in human upper small intestine: duodenum, jeJunum Blood-Lung migration: skin --- lymphatic system right side of the heart ---lung - respiratory tree coughed up and swallowed ---small intestineLife cycle • No intermediate host is necessary • Larva takes a free living mode • The filariform larva is the infective stage • Infection routes: skin penetration(mainly); orally swallow; maternal-child • Residing in human upper small intestine: duodenum, jejunum • Blood-Lung migration: skin --- lymphatic system --- right side of the heart --- lung --- respiratory tree --- coughed up and swallowed --- small intestine