Vulpes vulpes: A possible wild reservoir for zoonotic filariae

Foxes (Vulpes vulpes, n = 132) killed during the hunting seasons 2005-2006 in Central Italy (Tuscany region) were examined in order to investigate the possible importance of this animal as a wild reservoir for zoonotic filariae. In each specimen adult worms of Dirofilaria immitis and hematic microfilariae were searched for. Species identification was performed by morphology, morphometry, the Barka staining technique applied to pulmonary and splenic blood smears, and, finally, by molecular diagnostics-polymerase chain reaction (PCR) and sequencing. Twenty-three subjects (17.4%) proved to be positive for filarial parasites. Infection by Acanthocheilonema was more widespread than by Dirofilaria. Briefly, 8 foxes harbored mature adults of D. immitis; two of them (25%) also had microfilariae that in one case were mixed with the microfilariae of D. repens. Twelve subjects had microfilariae of Acanthocheilonema reconditum, and 3 harbored microfilariae of A. dracunculoides. Molecular diagnostics confirmed all results. Our findings, drawn by the examination of a few microliters of blood obtained from foxes approximately < 2 years of age, support the hypothesis that this animal may be an abundant source of infection for ticks that transmit Acanthocheilonema parasites and for mosquitoes that act as vectors for dirofilarial nematodes. Therefore foxes, contributing to the parasite circulation in areas where dogs usually undergo prophylactic treatment, have to be considered an important wild reservoir for filarial parasites that can be transmitted to companion animals and people.