Immunization of young foxes against rabies: interaction between vaccination and natural infection.

A preliminary experiment of vaccination against rabies with a parenterally administered killed vaccine was performed in Belgium with young foxes (Vulpes vulpes L.) captured in an enzootic area (Province de Luxembourg). Out of 20 young foxes, 12 developed spontaneous rabies. Vaccination induced a rapid and important seroconversion in most of the non rabid animals but failed to stop the evolution of the disease in young foxes incubating rabies. On the contrary, vaccination seemed to accelerate the evolution.