DURATION OF IMMUNITY IN FOXES VACCINATED ORALLY WITH ERA VACCINE IN ABAIT

Red foxes (Vulpes vulpes) vaccinated orally with the ERA strain of rab ies vaccine in a bait were challenged after 83 mo, Ten of 11 foxes tha t had seroconverted following vaccination resisted challenge with a vi rulent rabies virus which produced clinical signs of rabies in 6 of 6 unvaccinated foxes. Five of 11 vaccinated animals retained titers of r abies virus neutralizing antibody throughout the period. Although 6 of 11 had no detectable antibody at the time of challenge, 5 of these 6 resisted challenge and had an anamnestic response, as indicated by ele vated titers of antibody when measured at day 77 postchallenge. These results show that foxes can be immunized successfully with a single or al dose of ERA vaccine, probably with protection against a lethal rabi es challenge, for at least 7 y.