Large-scale eradication of rabies using recombinant vaccinia-rabies vaccine

Abstract

RABIES infection of domestic and wild animals is a serious problem throughout the world. The major disease vector in Europe is the red fox (Vulpes vulpes) and rabies control has focused on vaccinating and/or culling foxes. Culling has not been effective, and the distribution of live vaccine baits is the only appropriate method for the vaccination of wild foxes¹. Although some European countries have conducted field vaccination campaigns using attenuated rabies virus strains^2-5, their use has not been extensively approved because they retain pathogenicity for rodents and can revert to virulence^6,7. These strains cannot be used in North America because they are pathogenic for the striped skunk(Mephitis mephitis)⁸ and are ineffective in the racoon (Procyonlotor)⁹. We have constructed a recombinant vaccinia virus10, VVTGgRAB, expressing the surface glycoprotein (G) of rabies virus (ERA strain)^11–13. The recombinant was a highly effective vaccine in experimental animals^11–13, in captive foxes^14,15 and in racoons⁹. We report here the results of a large-scale campaign of fox vaccination in a 2,200 km² region of southern Belgium, an area in which rabies is prevalent. After distribution, 81% of foxes inspected were positive for tetracycline, a biomarker included in the vaccine bait and, other than one rabid fox detected close to the periphery of the treated area, no case of rabies, either in foxes or in domestic livestock, has been reported in the area.