In 1994, raccoon rabies was rapidly approaching the highly urbanized Pinellas County, Florida peninsula after a 30 year hiatus. With a high population of urban raccoons as the spark and feral/outdoor cats as the tinder, raccoon rabies was poised to sweep through Pinellas County like a raging forest fire. In 1994, the county had received state approval to distribute the oral wildlife vaccine-bait, Raboral V-RGŪ. After the raccoon rabies epizootic exploded in early 1995, the plan was implemented when the USDA finally granted conditional licensure for Raboral V-RGŪ which allowed purchase of the vaccine-bait in May 1995. The objectives of the three year campaign were to limit the spread of the outbreak and to reduce the number of positive rabies cases by 50% in each succeeding year. In 1995, 85,000 vaccine-bait units were distributed, primarily by helicopter. In 1996, 115,000 vaccine-baits were distributed by helicopter and ground treatment teams. From a pre-treatment baseline of 2% of the raccoons with positive rabies antibody titers, the second year’s results were encouraging. Of 206 raccoons tested, 38% had positive rabies antibody titers, and 55% of these raccoons were positive for the tetracycline biomarker contained in the vaccine-bait. Rather than sweeping the small, 20 km by 70 km peninsula, the positive rabies cases were clustered along a narrow mid-county corridor. The number of positive rabies cases dropped from 30 in 1995, to 18 in 1996. The number of humans receiving post-exposure treatment decreased by 30%, to 101 cases from the previous year’s 145 cases. In 1997, 130, 320 vaccine-bait units were distributed by helicopter and ground treatment teams. The number of positive cases in animals continued to decrease with only two positive cases in 1997 which led to the lifting of the remaining quarantine zone in June. Of 272 raccoons tested, 36% had positive rabies antibody titers and of 244 tested for tetracycline biomarker, 58% were positive. From the random backyard samples the 1997 results were 50% positive for tetracycline biomarker compared to 24% positive in 1996. These results reflect improved distribution by ground control treatment teams. The number of humans receiving post-exposure treatment decreased by 53%, to 43 cases from the previous year’s 101 cases. In June 1998, 129,000 vaccine baits were distributed by helicopter and ground treatment teams after a delay due to unseasonal rainfall caused by El Nino. Only one case of terrestrial rabies was reported in 1998. These results indicate that Raboral V-RGŪ is an effective weapon to augment traditional rabies control measures in an urban area. The wildlife rabies vaccine campaign has been well received by the public. Additionally, the educational value and positive public relations impact have been significant secondary benefits of the campaign which has been extended to run through 1999. Future years’ plans call for the distribution of a smaller number of baits along the neck of the peninsula to create a barrier, combined with spot treatment around any isolated case of rabies.

Other Florida counties have expressed interest in using oral rabies vaccines (ORV) in their control efforts. Recently the United States Department of Agriculture has made funding available for ORV programs-$1.2 million in 1998 - through USDA Wildlife Services. Currently legislation is being drafted to increase the levels of funding significantly in the coming years. None of the funds are slated for Florida at this time. If your local government has an interest in federal funding for an ORV program, contact your congressional representative. If you "can’t stand the pain" of waiting for raccoon rabies to burn out in your area, you might consider ORV as an additional weapon in your program. Conditional licensure of ORV restricts its use to state approved programs. Protocols should be submitted to Dr. Lisa Conti, State Public Health Veterinarian. Protocols must be reviewed and approved by the Rabies Control Committee.

Merial’s oral vaccinia-vector recombinant rabies vaccine (Raboral V-RG) for raccoons was approved by the USDA for field trial in Virginia in 1990. Additional field trials were later approved in New Jersey, Massachusetts and New York. Raboral V-RG rabies vaccine is now being used in Texas to combat the coyote rabies epizootic in south Texas, and the fox rabies in west Texas. The attenuated vectored vaccine’s transport virus is derived from vaccinia virus and carries the gene for the rabies glycoprotein. A vaccine-laden block of fish meal attracts the animal. When ingested the vaccinia virus can be isolated from the tonsils, where it produces an immune response. The vaccine proved to be efficacious in both controlled laboratory and field studies according to the Centers for Disease Control and Prevention.