New insights into trematode infections in cattle and their snail intermediate hosts in a Mediterranean area of Italy

This study investigated snails collected from eleven cattle farms in a Mediterranean area of southern Italy, where Fasciola hepatica (liver fluke) and Calicophoron daubneyi (rumen fluke) are known to occur. A total of 319 snails were collected from various aquatic habitats across the selected farms and identified using morphological and molecular analysis. BLAST analysis revealed two snail species: Galba truncatula (56.7 %) and Physella acuta (43.3 %). Statistical analyses revealed that shell and aperture lengths differed significantly between the two snail species. A subset of 130 snails was tested for the presence of F. hepatica and C. daubneyi DNA. Snails were initially tested in pools of ten individuals per species and single snails from positive pools were subsequently examined individually. Fasciola hepatica DNA was detected exclusively in G. truncatula , whereas C. daubneyi DNA was found in both G. truncatula and P. acuta . In addition, a total of 84 adult liver flukes were collected from cattle on seven of the eleven farms, morphometrically characterized, and molecularly confirmed as F. hepatica . The concurrent detection of fluke eggs in cattle faeces, adult flukes in livers and fluke DNA in snails suggests that active transmission is ongoing on these farms. Galba truncatula , already established as the main intermediate host for both F. hepatica and C. daubneyi in Europe, was confirmed in this study as naturally infected with both flukes under Italian field conditions. Broader seasonal surveys are warranted to better define infection dynamics. In contrast, the detection of C. daubneyi DNA in P. acuta requires experimental confirmation of cercarial shedding and infectivity to the definitive host to determine its actual role in fluke transmission.