[Importance of the fox (Vulpes vulpes) in the transmission of sarcosporidiosis from the steinbock (Capra ibex) at the Gran Paradiso National Park]

Abstract

Sarcosporidiasis is a very common infection of steinbocks (Capra ibex) and chamois (Rupicapra rupicapra) of Gran Paradiso National Park, Italian Western Alps, frequently with serious cardiac involvement. No dogs or cats are allowed inside the Park, to the contrary foxes (Vulpes vulpes) are present every where, near steinbocks and chamois, and eat on the bodies of dead animals. Feces of Vulpes vulpes were collected in the same area, where the infected Capra ibex used for the following experiment was living (Gran Nomenon - Chantel - P.N.G.P. Val di Cogne, altitude ranging from 2200 to 2600 m). These feces and feces from foxes collected in different areas of Valle dell'Orco were found positive for sporulated sporocysts which varied between 8-10 X 13-15 mum. Infected muscles of a Capra ibex (oesophagus, heart, diaphragm, intercostal and abdominal muscles, etc.) were fed to canidae (Vulpes vulpes, Canis lupus and Canis familiaris), felidae (Felis catus, Felis leo) mustelidae (Putorius putorius furo) and to a prey bird (Falco tinnunculus). One Vulpes vulpes and two Canis familiaris were maintained as control under the same experimental conditions. Only Vulpes vulpes, Canis lupus and Canis familiaris excreted sporulated sporocysts in their feces after 12, 13 and 21 days respectively and for several weeks. These sporocysts varied between 8-10 X 13-15 mum. All the other animals (Felis catus, Felis leo, Putorius putorius furo and Falco tinnunculus) remained costantly negative during all the experiments. It is concluded that Vulpes vulpes, Canis lupus and Canis familiaris (Canidae) are definitive hosts of Sarcocystis sp. of Capra ibes of P.N.G.P., and that sarcosporidiasis of steinbocks is transmitted inside the Parco (P.N.G.P.) by Vulpes vulpes.