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Background Fascioloides magna is a pathogenic fluke introduced to Europe ca 140 years ago. As it is spreading over the continent, new intermediate and definitive hosts might be involved in transmission of the parasite. In Europe, several studies reported potential new intermediate snail hosts (Radix spp.) for F. magna, and also several cases of fascioloidosis of wild and domestic animals were published. However, the data based on molecular and histological analyses confirming these findings remained unreported. This study aims to refer to unique findings of F. magna in European snails and domestic animals (the first observation in the Czech Republic in the last 30 years) and demonstrate the use of molecular techniques in determination of F. magna. Results Two snails of R. labiata naturally infected with F. magna were found; mature cercariae and daughter rediae were observed. Maturity of cercariae was checked by histological methods, however, their ability to encyst was not confirmed. Co-infection of F. magna and Fasciola hepatica in the liver of two highland cattle bulls was proved. Adult fasciolid flukes producing eggs were found in the liver pseudocysts (F. magna) and the bile ducts (F. hepatica). Identification of intermediate hosts, intramolluscan stages, adult flukes and eggs was performed by sequencing the ITS2 region. Connection of F. magna pseudocysts with the gut (via the bile ducts) was not confirmed by means of histological and coprological examinations. Conclusions For the first time, Radix labiata was confirmed as the snail host for F. magna under natural conditions and, together with the finding of F. magna infection in cattle, we can expect further transmission of F. magna from wildlife to livestock in localities shared by these hosts. [ABSTRACT FROM AUTHOR]

Radix labiata is a widely distributed Palaearctic freshwater snail. This work aims to improve the knowledge of the intraspecific variability in the most important characters used for its determination. To find out which characters are really suitable to distinguish this species from other similar Radix species an integrative approach was applied, involving morphological and molecular data. Molecular sequences of the nuclear spacer fragment ITS-2 and/or the mitochondrial gene fragment cyt-b were obtained from 26 individuals of R. labiata from different regions of Europe, including type localities of Limnaeus pereger labiatus. From the subsample of 24 specimens of which sequences of both gene fragments were available, the variability of several characters that are commonly used for species identification (shell morphology, mantle pigmentation, shape and position of the bursa copulatrix, length and position of the bursa duct, length ratio of praeputium to penial sheath) were measured or documented. Morphological characters distinguishing R. labiata from R. balthica, R. lagotis and the genus Stagnicola are discussed. The best morphological character to differentiate these species is the position of the bursa and the bursa duct. Mantle pigmentation and the ratio of the length of the praeputium to that of the penial sheath are not useful for differentiating R. labiata and R. balthica. Analysis of the network of haplotypes (cyt-b) revealed no correlation between recognisable clusters and geography amongst the studied specimens. [ABSTRACT FROM AUTHOR]