EUROPEAN RED FOXES (VULPES VULPES) AS A POSSIBLE RESERVOIR FOR CANINE ADENOVIRUS TYPE 1 (CADV-1)

Introduction: In European red foxes (Vulpes vulpes), CAdV-1 infection is occasionally reported as a cause of illness (epizootic fox encephalitis and infectious canine hepatitis) and evidence of exposure to CAdV-1 has been confirmed in different European countries. Materials and Methods: Fifty-seven red foxes of both genders (38 males and 19 females) and different ages (11 juveniles and 46 adults), shot during the regular hunting season in central Italy (36 animals) and the North-West of England (21 animals) underwent full post mortem examination. A complete set of organs was sampled for histopathology, hepatic and renal samples were tested for CAdV by PCR and immunohistochemistry (IHC). Results: All foxes were in fair to good body condition with 12/57 (21%) presenting different degrees of sarcoptic mange. PCR performed on renal samples showed CAdV-1 specific amplicon, encompassing E3 gene and flanking regions, in 18/57 foxes (31.5%) with similar prevalence in both Italian and UK subjects. Hepatic samples were always PCR-negative. Histopathology did not reveal any lesions suggestive of CAdV-1 and IHC was negative in hepatic and renal samples. Four positive amplicons (two Italian and two English) were sequenced with high identity rate of 99.9% and phylogenetic analysis confirmed CAdV-1 homology for all the sequences analysed. Conclusion: The presence of CAdV-1 infection in foxes could represent a problem for both wild animals and domestic dogs. Our data confirms the central role of red foxes in Europe play as a possible reservoir rather than as an incidental host in maintaining this virus in the territory.