The performance of a PCR assay for field studies on the prevalence of Fasciola hepatica infection in Galba truncatula intermediate host snails.

The aim of this work was to develop a PCR assay for the detection of F. hepatica in Galba truncatula snails and to evaluate its performance in field studies. Primers were designed to amplify a 124bp non-coding tandem repeat found in the Fasciola genome. The result was a banding pattern corresponding to multiples of the initial target sequence. The sensitivity of the PCR was determined on experimentally infected snails. The test was sensitive enough to detect fluke DNA in snails experimentally infected with 1 miracidium, within 12h after exposure. The specificity was determined with Dicrocoelium dendriticum, Paramphistomum cervi and snail DNA. No cross-reactions occurred with DNA of the trematodes or snail DNA. G. truncatula specimens were collected from 4 localities in Eastern Poland, with a total of 192 snails from 12 habitats. The overall prevalence of F. hepatica infection was 26.6% (51/192), ranging from 21.4% to 84.6% in the individual sites. The designed assay was shown to be a valuable epidemiological tool for the purpose of snail infection monitoring. The results on F. hepatica prevalence in snail hosts are the first data from Poland since the 1950s and the only such data based on molecular methods.