Presence of Alaria alata in Red Foxes (Vulpes vulpes) in North West Italy

Introduction:  Alaria alata is a common intestinal trematode of red foxes in European countries. However, its presence in Italy has been rarely reported. The complex life cycle of A. alata requires a freshwater snail as the first intermediate host and an amphibian as the second one. Reptiles, rodents, wild boars, and other vertebrates can act as paratenic hosts after feeding on infected amphibians. Alaria alatais is regarded as a potential zoonotic agent, especially considering the contamination of wild boar meat with viable mesocercariae.

Purpose: The aim of the study was to determine the presence of the parasite in north west Italy.

Methods: Between 2013 and 2015, the gastrointestinal tracts of 100 red foxes, chosen by convenience, were sampled by the Fish and Wildlife Service. Trematodes morphologically consistent with A. alata were submitted for molecular identification by amplification and sequencing of the D2 region of the 28S rRNA gene and the mitochondrial COI gene.

Results:  Of the sampled foxes (n=100), 20% were found positive for the presence of trematodes morphologically consistent with A. alata. However, molecular identification of the species was not successful: the analysis of the sequences of both genes indicated that the parasites found in this study belonged to a different group of digenean species.

Significance: Our study demonstrated the presence of a previously unknown digenean parasite, morphologically similar to Alaria spp., but genetically quite distinct. Further studies are in place for the taxonomic identification and the description of its biological characteristics, including the pathogenic and zoonotic potential.