Effectiveness of Chaetogaster limnaei as a controller of Fasciola hepatica in experimental infections of Galba truncatula

BACKGROUND: Chaetogaster limnaei is an annelid symbiotically associated with lymnaeid snails as Galba truncatula. This association is considered a preventive mechanism against trematode miracidia infection, including Fasciola hepatica. The objective of this study was to determine the effectiveness of Chaetogaster limnaei as a natural controller of Fasciola hepatica in laboratory conditions. PROCEDURES: Fascsola hepatica miracidia were inoculated in parallel into snails carrying Chaetogaster limnaei and snails without the annelid. The degree of infection was measured after 40 days of exposure. Furthermore, the number of annelids per snail was quantified, as well as the ability of Chaetogaster limnaei to devour miracidia at different times of exposure. RESULTS: An effective 70% natural control of Fasciola hepatica in Galba truncatula was observed. The carrying capacity of the snail was established to be of 10.6 ± 1 annelids. Chaetogaster limnaei is a predator of Fasciola hepatica devouring an average of 3.79 ± 0.21 miracidia. The results of these experiments have a potential value as a control measure against fascioliasis in the environment.