Susceptibility of some fresh water snails of Portugal and Spain to Fasciola hepatica

Malacological Research has often confirmed that L. truncatula is only seldom, or even not at all found in fascioliais areas, while P. acuta and L.peregra show a wide dense distribution: on the other hand, these snails may act as relative vectors in other countries. The question, therefore, arises of the whether or not they are vectors for F. hepatica in the Iberian Peningula. From the experiments conducted itmay be concluded that fascioliasis in the Iberian Peninsula depende mainly on L. truncatula since, in Spain, none of the other snalis tested was shown to be a vector, and in Portugal only L. palustris could be shown to act as a relative vector. Infection rates were 52.5%, 47.9% and 100% respectively. This led to a more detailed investigation on the species geographical distribution on Portugal which enabled the authors to conclude, that L. truncatula is more common in this country than was previously thought. The initial lack of overlap found in the occurrence of L. truncatula is fascioliasis areas should be atributed to initial difficulties not only in locating the minute-size and amphibious snails in their differente habitats, but also in distinguisly the same habitats types. From the three groups of experiments condute itmay be concluded thah fascioliasis in the Iberian Peninsula depends mainly on L. truncatula, L stagnalis, P. acuta and L. peregra from both countries showed resistance to infection.