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Rabies in Free Ranging Wildlife

photo of skunk

Investigating the Ecology Control and Prevention of Terrestrial Rabies in Free-Ranging Wildlife

Research Project

Rabies, one of the oldest known diseases affecting humans, is an acute, fatal viral zoonosis most often transmitted through the bite of a rabid mammal. In the United States, terrestrial rabies is maintained in several distinct strains in raccoons, skunks, gray foxes, arctic foxes, and coyotes.

Although human rabies deaths are now rare in the United States, there are significant impacts associated with the disease. The estimated public health costs associated with rabies have risen to over $300 million annually, with the number of individuals receiving post-exposure prophylaxis estimated annually at 40,000. If rabies strains such as those transmitted by raccoons, gray foxes, and coyotes are not prevented from spreading to new areas of the United States, the health threats and costs associated with rabies are expected to increase substantially as broader geographic areas are affected.

Raccoon rabies is now enzootic in all of the eastern coastal states, as well as Pennsylvania, ermont, West Virginia, and parts of Alabama, Tennessee, and Ohio. In the past 25 years, all of the mid-Atlantic and New England states have experienced at least one outbreak. The raccoon rabies front reached Maine in 1994, and northeastern Ohio in 1996.

To combat this growing threat, a vaccine was developed for the oral vaccination of select wildlife species against rabies. Raboral V-RG® confers immunity against rabies virus in select wildlife species. At present, it is the only licensed oral vaccine for rabies control in select wild carnivores in the United States. NWRC researchers have completed or are near completion of studies evaluating various bait densities for raccoons, acceptance of placebo baits by skunks, evaluations of raccoon movements in Alabama, evaluations of the effects of ORVs on nontarget wildlife, and manipulation and consumption of ORV baits by raccoons. Additional, long-term studies to be pursued include immunological responses of raccoons to ORVs; movements and ecology of gray foxes and other reservoir species; natural wildlife movement barriers; more efficient delivery systems for vaccines; better baits and biomarkers for vaccine baits; and biosafety studies for newly developed vaccines.

Project Leader:
Dr. Amy Gilbert
Fort Collins, Colorado 80521
(970) 266-6054

Project Factsheet: 

Economic Benefits of Oral Rabies Vaccination

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Project Goal and Objectives

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