Rabies immunization of red foxes (Vulpes fulva) with vaccine in sausage baits.

Foxes were orally vaccinated against rabies with two modified live vaccine viruses, ERA/BHK-21 and PRI strain, in sausage baits. The baits proved acceptable to caged foxes and effectively delivered immunizing doses of vaccine. Antibody profiles on the vaccinated foxes and intramuscular challenge with "street" rabies virus showed the ERA/BHK-21 vaccine to be more effective than the PRI vaccine. The addition of a stabilizer helped maintain virus titers when the baits were subjected to high (35 C) temperature.