Detection of Planorbis planorbis and Anisus vortex as first intermediate hosts of Alaria alata (Goeze, 1792) in natural conditions in France: molecular evidence.

Alaria alata (Goeze, 1792), a trematode that parasitizes canids, usually needs two intermediate hosts to complete its life cycle: an aquatic freshwater snail and an amphibian. Although many studies have been undertaken on the wild boar's role as paratenic host, owing to the potential threat to human health, few have sought to identify the snails that act as first intermediate hosts in natural conditions. Adopting a molecular approach, with specific markers for a portion of the second internal transcribed spacer (ITS-2), we detected haplotypes of A. alata furcocercariae in two snail species (Planorbis planorbis and Anisus vortex), identified by molecular analysis (ribosomal 18S, mitochondrial 16S and COI). This study provides the first description of snails naturally emitting A. alata furcocercaria in Western Europe.