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We studied the population genetic structure of the freshwater snail Galba schirazensis (Küster, 1862), a potential vector of infectious diseases such as fascioliasis. Galba schirazensis has now a worldwide distribution but a poorly known origin because this species has been distinguished only recently from the morphologically similar and cosmopolitan Galba truncatula (O.F. Müller, 1774). We developed specific microsatellite markers and sequenced a mitochondrial gene (cytochrome oxidase subunit I ( CO1)) to study individuals of G. schirazensis from the Old World and the New World. We found very low genetic diversity within populations, no heterozygotes, and marked population structure - a pattern observed in other highly selfing lymnaeid species with recently enlarged distributions as a result of biological invasions. The total lack of observed heterozygosity in the few populations of G. schirazensis that displayed some allelic diversity suggests high selfing rates. We also found that the center of diversity, and by extension the origin area of this species, should be found in the New World, whereas Old World populations should rather result from a recent introduction of a genetically uniform population. The microsatellite markers developed here will help to clarify the history of expansion of G. schirazensis and might help to understand its role as a potential vector of infectious diseases. [ABSTRACT FROM AUTHOR]

Experimental infections of Galba sp. (origin, Colombia) with allopatric isolates of Fasciola hepatica from France or Fascioloides magna from the Czech Republic were carried out during five successive snail generations to determine if this lymnaeid might sustain complete larval development of either parasite. In snails exposed to F. hepatica, 7 of 400 snails harboured several rediae and only two snails contained a small number of free cercariae on day 50 post-exposure. In contrast, the intensity of F. magna infection in Galba sp. progressively increased from the F1 to F5 generations. Spontaneous cercarial shedding of F. magna occurred in 7 of 100 Galba sp. belonging to the F5 generation and the number of shed cercariae did not differ significantly from that noted in control Galba truncatula of French origin. Galba sp. from Colombia can be added to the list of potential intermediate hosts for F. magna. [ABSTRACT FROM AUTHOR]

A wild population of the lymnaeid snail Pseudosuccinea columella infected by larval stages of Fasciola hepatica was discovered in the Pinar del Río Province, Cuba. One of 100 snails was infected in a rice culture field. This is the first time this species has been found acting as intermediate host of F. hepatica under natural conditions, not only for Cuba but also for the Caribbean area. [ABSTRACT FROM AUTHOR]