Leptospirosis in red foxes in Ontario

The role of the red fox (Vulpes vulpes) in the epizootiology of leptospirosis in southwestern Ontario was investigated in 1973-1974. Leptospira interrogans serovar pomona (kennewicki by DNA analysis) was isolated from the kidneys of three of eight foxes tested. Severe hemorrhagic nephritis and interstitial nephritis were common to these foxes and to five others out of nine foxes examined. Autumnalis antibodies were detected at titers 10(-2) to 10(-5) in 12 of 100 fox sera. Pomona antibodies occurred in 6% of the sera, always accompanied by autumnalis antibodies, and at titers never exceeding the autumnalis titers. Cultural, serological, and pathological findings together indicated that the red fox could have been acting as an amplifier host, but not as a maintenance host, for pomona.