Fasciola gigantica Cobbold 1856 in the snail

Intramolluscan stages of Fasciola gigantica were followed experimentally in laboratory-reared Lymnaea natalensis, from the time of miracidial entry until the 85th day. Contrary to previous accounts, the miracidium was found to metamorphose directly into a first-generation redia during the first 4 days. About the 16th day, the redia migrated to the snail liver. Second-generation rediae gave rise to 3rd-generation rediae and/or cercariae by the 45th to 50th day. The release of cercariae from 3rd-generation rediae began around the 75th day, and from 4th-generation rediae after 85 days. All studies were conducted at ambient temperatures in the laboratory at Makerere University, Kampala, Uganda, in 1968-71.