SOME BIOLOGICAL CHARACTERISTICS OF LYMNAEA TRUNCATULA AND LABORATORY PRODUCTION OF FASCIOLA HEPATICA METACERCARIAE

Abstract

A study was made on some aspects of the biology of Lymnaea tn.nicatula and production
of metacercariae of Fasciola hepatica under laboratory conditions. The experiment was conducted using
laboratory bred snails originally collected from Debre Brihan area. The snails were maintained on blue
green algae (Nos toe vascoruni) grown in the laboratory. Snails laid masses of eggs with mean±SD
number of 7.8±2.8 eggs per capsule, 96.7% of them having one egg cell per egg. Hatchability was 86.9%.
Mean age at maturity was 6,1.8±11 days. Survival of snails post-infection was inversely related to the
miracidia I injective dose. Higher proportion of snails infected with small number of miracidia shed
more cercariae than those infected with larger number of miracidia. Young snails were less susceptible
to infection and survived longer than adult snails post-infection. Younger snails also shed lower
number 'of cercariae than the fully-grown adult snails. The study showed that both young and adult
snails can be infected with miracidia and shed cercariae at different levels.. Both the age of snails and
miraddiaI infective dose influenced the susceptibility of snails to miracidial infection and production of
cercariae.