The epidemiology of fascioliasis in Malawi: I. The epidemiology in the intermediate host.

Fasciola gigantica Cobbold was studied in the intermediate host snail. On snail survey Lymnaea natalensis Krauss was the species found responsible for the transmission of Fasciola gigantica in Malawi. The ecology of this snail was studied at 5 different habitats spread throughout Malawi. The snail population was recorded high from April to October. The epidemiological cycle of Fasciola gigantica in the snail was determined and it was shown that snail infection was high in April and May and thus more metacercariae are released in August to October following such an infection. To complete the epidemiological picture studies reported separately were done involving the definitive host.