Efficacy and bait acceptance of vaccinia vectored rabies glycoprotein vaccine in captive foxes (Vulpes vulpes), raccoon dogs (Nyctereutes procyonoides) and dogs (Canis familiaris).

The red fox, dog, and raccoon dog are known to play a major role in the global epidemiology of rabies. These three canid species were used to compare the appetency and efficacy of two commercial bait formats, each containing a single dose of vaccinia-rabies glycoprotein (V-RG) vaccine. Square and rectangular RABORAL V-RG baits were fed to individual caged animal, and results were evaluated using three parameters: bait consumption, induction of rabies virus neutralizing antibodies and protection after a virulent rabies challenge. The rectangular and square RABORAL V-RG baits were found to deliver the oral rabies vaccine in a similar manner to all three species resulting in acceptable seroconversion and effective protection levels after the rabies challenge. Appetency of each bait type was measured by bait consumption and found to be similar for both RABORAL V-RG bait formats in the fox and dog. The square RABORAL V-RG bait, however, was consumed more effectively than the rectangular RABORAL V-RG bait by the raccoon dog.

Efficacy of a square presentation of V-RG vaccine baits in red fox, domestic dog and raccoon dog.

Oral vaccination programmes conducted in rabies infected countries from Eastern Europe and Eurasia should not be restricted to foxes but should target other major rabies vectors such as dogs and raccoon dogs as well. The objective of this experimental trial was to assess the protection induced by the vaccine by challenging these different species, which had been previously vaccinated intramuscularly with the square V-RG baits (produced in the US). Different parameters were evaluated such as attractiveness of the baits and induction of neutralising antibodies as an indicator for immunogenicity and protection after rabies challenge. The acceptability of the square bait was satisfactory in dogs, foxes and raccoon dogs, confirming previous laboratory and field studies conducted with the rectangular baits. Only one vaccinated dog out of nine seroconverted after vaccination and among them one dog died of rabies. Eight of ten vaccinated foxes seroconverted after vaccination and survived the rabies challenge. All vaccinated raccoon dogs seroconverted after challenge and all survived the challenge. These trials demonstrated that the square presentation of the V-RG vaccine was attractive, immunogenic and efficacious.