SREL Reprint #3726

Interspecific oral rabies vaccine bait competition in the Southeast United States

Wesley C. Dixon1,2, Jacob E. Hill1, Richard B. Chipman3, Amy J. Davis4, Amy T. Gilbert4,
James C. Beasley1,2, Olin E. Rhodes Jr.1,5, and Guha Dharmarajan1

1Savannah River Ecology Laboratory, University of Georgia, PO Drawer E, Aiken, SC 29802, USA
2Warnell School of Forestry and Natural Resources, University of Georgia, 180 E Green St,
Athens, GA 30602, USA
3National Rabies Management Program, USDA, APHIS, Wildlife Services, 59 Chenell Drive, Suite 2,
Concord, NH 03301, USA
4National Wildlife Research Center, USDA, APHIS, Wildlife Services, 4101 Laporte Ave,
Fort Collins, CO 80521, USA
5Odum School of Ecology, University of Georgia, 140 E Green St, Athens, GA, 30602, USA

Abstract: The United States Department of Agriculture’s National Rabies Management Program (NRMP) has coordinated the use of oral rabies vaccination (ORV) to control the spread of raccoon rabies virus variant west of the Appalachian Mountains since 1997. Working with state and local partners, the NRMP deploys ORV baits containing a rabies vaccine, primarily targeting raccoon populations (Procyon lotor). Bait competition between raccoons and non-target species may limit the effectiveness of ORV programs, but the extent of bait competition remains poorly quantified, particularly in the southeastern United States. We placed placebo ORV baits in bottomland hardwood (n = 637 baits) and upland pine (n = 681 baits) habitats in South Carolina, USA during August-December 2019 and used remote cameras to examine bait competition between raccoons and non-target species. The estimated proportion of bait consumed by raccoons was 18.8 ± 2.1% in bottomland hardwood and 11.6 ± 2.1% in upland pine habitats. Vertebrate competition appeared to have a minimal effect on raccoon uptake as estimated consumption did not exceed 5% for any species or 8% of bait uptake events cumulatively. We estimated that raccoons were the primary consumer of baits in bottomland hardwood, whereas invertebrates were the primary consumer in upland pine (26.7 ± 1.3% of baits). Our results indicate a need to closely consider the effects of invertebrates on bait consumption to minimize their potential impact on ORV bait uptake by target species. Uptake probabilities by raccoons were relatively low but not primarily driven by competition with vertebrates. As such, strategies to increase the specificity of raccoon uptake may be needed to enhance the effectiveness of ORV baiting programs.

Keywords: Bait competition; Camera trapping; Oral rabies vaccination; Procyon lotor; Rabies; Raccoon

SREL Reprint #3726

Dixon, W. C., J. E. Hill, R. B. Chipman, A. J. Davis, A. T. Gilbert, J. C. Beasley, O. E. Rhodes Jr., and G. Dharmarajan. 2023. Interspecific oral rabies vaccine bait competition in the Southeast United States. Applied Animal Behaviour Science 261: 105897.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).