Contact Information: 

Dr. Kurt C. VerCauteren 

Supervisory Research Wildlife Biologist

NWRC Headquarters

4101 LaPorte Avenue

Fort Collins, CO 80521

Phone: (970) 266-6093 

FAX: (970) 266-6157

kurt.c.vercauteren@aphis.usda.gov

www.aphis.usda.gov/wildlife_damage/

nwrc/ 

• Major Cooperators

• Artemis Technologies

• Centers for Disease Control and Prevention

• Cleveland Metroparks

• FoodSource 

• Global Alliance for Rabies Control

• Kansas State University

• Lyssa, LLC

• MERIAL, Inc.

• New Mexico State University

• Purdue University

• Texas A&M University

• Texas State Department of Health 

Services

• University of Georgia

• University of Tennessee

• Wildlife Services Operations

Wildlife Services

Protecting People rotecting People

Protecting Agriculture rotecting Agriculture

Protecting Wildlife rotecting Wildlife

FY 2012

National Wildlife Research Center

United States Department of Agriculture

Animal and Plant Health Inspection Service

National Wildlife Research Center Scientists Develop New Methods, Strategies to Reduce Rabies Transmission from Infected Wildlife to Humans, 

Domestic Animals, and Wildlife

Wildlife Services’ (WS) National Wildlife Research Center (NWRC) is the only Federal 

research organization devoted exclusively to resolving confl icts between people and 

wildlife through the development of effective, selective, and socially responsible methods, tools, and techniques.

Increased urbanization, greater acceptance of and desire for living closer to free-ranging 

wildlife, and burgeoning wildlife numbers have led to increased confl ict between people 

and wildlife. Such confl ict can take many forms, including the transmission of diseases 

among wildlife, livestock, and humans. Indeed, many of the pathogens that cause animal 

disease also are capable of causing disease in humans. Appropriately, there is a great 

need to understand the processes mediating disease transmission among wildlife, 

livestock, and humans.

Rabies is an acute, fatal viral disease, most often transmitted through the bite of a rabid 

mammal, which can infect people as well as animals. Impacts to society from this and 

other wildlife diseases can be great. For instance, the cost of detection, prevention, and 

control of rabies in the United States exceeds $300 million annually. 

In 2000, the Secretary of Agriculture enacted a Declaration of Emergency for rabies, 

citing threats to livestock and to public health and safety. In 2001, NWRC initiated research to help reduce the transmission of this disease.

In the United States terrestrial rabies can be found in many wild animals, including raccoons, skunks, gray foxes, arctic foxes, bobcats, and coyotes. In an effort to halt the 

spread and eventually eliminate terrestrial rabies in the United States, NWRC scientists 

are researching the behavior, ecology, movement, and population structure of raccoons 

and other wildlife hosts. They also are evaluating methods and techniques used to vaccinate wildlife against rabies to decrease the risk of transmission and maintenance of the 

disease in the wild.

Applying Science & Expertise to Wildlife Challenges

Safety and Effi cacy of ONRAB® in Target and Nontarget Species—NWRC researchers are exploring a new oral rabies vaccine (ORV) called ONRAB for use on raccoons 

and skunks in the United States. In an initial fi eld trial in West Virginia, ONRAB resulted 

in the highest seroconversion rate in raccoons ever observed for an ORV bait used in the 

United States with 49.4 percent of raccoons showing seroconversion post-ORV versus 

9.6 percent pre-ORV. Unfortunately, the skunk sample size was too low to adequately 

assess the effects of the vaccine on skunks. In addition to conducting fi eld trials with 

the target species, researchers also investigated the effects of the vaccine on nontarget 

species including wood rats, eastern cottontail rabbits, opossums, eastern wild turkey, 

and fox squirrels. These are all species whose habitats overlap with ORV target species. Evaluations of non-target species were conducted with captive animals and NWRC 

researchers tested fecal and oral swabs from animals dosed with the ONRAB vaccine at 

10 times the rate that they could be exposed to in the wild. Viral ribonucleic acid (RNA) 

was detected in turkey feces up to 3 days post inoculation (dpi), opossum feces up to 6 

dpi, cottontail feces up to 5 dpi, and fox squirrel feces through 7 dpi. Although over 40 

percent of fox squirrels were still shedding viral RNA on 7 dpi, some showed signs of coinfections with Leptospira spp. This co-infection may have made them more susceptible 

to the vaccine or may have interfered with the test, resulting in false-positives. Minimal 

Ecology, Control, and Prevention of cology, Control, and Prevention of 

Terrestrial Rabies in Free-ranging errestrial Rabies in Free-ranging Wildlife ildlife

• Groups Affected By These Problems

• Consumers

• Health offi cials

• Livestock producers and farmers 

• Sporting organizations

• Veterinarians

• Wildlife and natural resource 

managers 
shedding was observed via oral routes (and opossum nasal 

swabs), demonstrating that ONRAB has very minimal and temporary impacts on these nontarget species even when exposed to 

10 times the expected dose. Results from these studies will aid in 

efforts to license ONRAB for use in the United States through the 

USDA-APHIS Center for Veterinary Biologics. 

Role of Water Availability in Rabies Transmission—Since 

rabies can infect multiple species and has a high potential for 

cross-species transmission, an understanding of the role water 

availability may play in facilitating disease transmission could 

lead to better disease prevention strategies. NWRC researchers 

collected data on interactions among coyotes, bobcats, and gray 

foxes at 31 artifi cial water features in Texas. Results indicated 

that gray foxes behaved as subordinate competitors for these 

water sources, having both the shortest time intervals at the 

sites and using them almost exclusively (greater than 97 percent 

of visits) at night. In contrast, only 41 percent of coyote and 61 

percent of bobcat visits to water sources occurred at night. Bobcats also spent more time at the sites, on average, than coyotes 

or gray foxes. The use of water sources by both coyotes and 

bobcats was directly related to the days since the last rainfall, 

with animals using artifi cial water sources more frequently as the 

time since last rainfall increased. Gray fox use of artifi cial water 

sources, on the other hand, was positively related to the availability of rugged escape terrain and inversely related to activity of the 

larger carnivores. These data suggest that while artifi cial water in 

arid environments of the southwestern United States may result 

in increased interactions and potential disease transmission 

among coyotes and bobcats, this may not be the case for gray 

foxes. Researchers also observed that 60 percent of the interspecies interactions recorded were between carnivores and cattle. 

These data indicate that the incidence of encounters at water features may be higher between carnivores and cattle than between 

carnivores and other carnivores, which suggests that these sites 

can lead to a higher probability of rabies virus transmission from 

wildlife to livestock. 

Use of Infrared Thermography to Detect Rabies in Bats—

The use of modern technology, including infrared thermography, 

in disease surveillance provides opportunities for insights into 

pathogen emergence, prevention, and control. This technology 

should have the capacity to identify diseased individuals within a 

population that are potentially manifesting clinical signs. NWRC 

researchers conducted a study that evaluated the use of infrared 

thermography to detect thermal changes associated with experimental rabies virus infection in big brown bats in a captive colony. 

Results indicated that when bats began to show clinical signs of 

rabies, 54 percent had detectable facial temperature decreases, 

compared to pre-inoculation temperatures. As a result, researchers believe that infrared thermography may be a useful noninvasive tool for use in rabies surveillance in bats. 

Selected Publications:

ATWOOD, T. C., T. L. FRY, and B. R. LELAND. 2011. Partitioning 

of a limited resource by sympatric carnivores in the Chihuahuan 

Desert and the implications for disease transmission. Journal of 

Wildlife Management 75: 1609-1615.

BEASLEY, J., W. BEATTY, T. C. ATWOOD, S. JOHNSON, and 

O. E. RHODES. 2012. A comparison of methods for estimating 

raccoon abundance: implications for disease vaccination 

programs. Journal of Wildlife Management 76(6):1290-1297.

FRY, T. L., T. C. ATWOOD, and M. R. DUNBAR. 2010. Evaluation of rhodamine B as a biomarker in raccoons. Human-Wildlife 

Interactions 4:275-282.

FRY, T., K. VANDALEN, J. HURLEY, and P. NASH. 2012. 

Mucosal adjuvants to improve wildlife rabies vaccination. 

Journal of Wildlife Diseases 48:1042-6. DOI: 10.7589/2011-

11-331.

SLATE, D., R. CHIPMAN, K. NELSON, C. CROSON, S. 

MILLS, C. RUPPRECHT, and K. VERCAUTEREN. Safety 

and immunogenicity of ONRAB in raccoons and skunks in 

West Virginia: 2011 fi eld trial report. USDA/APHIS/WS/National Rabies Management Program. Report to USDA/VS/

Center for Veterinary Biologics.

VERCAUTEREN, K., T. DELIBERTO, S. SHWIFF, C. ELLIS, 

R. CHIPMAN, and D. SLATE. 2012. Rabies in North America: 

need and call for a One Health Approach. In: Frey, S.N., editor. Proceedings of the 14th Wildlife Damage Management 

Conference, April 18-21, 2011, Nebraska City, NE; The Wildlife 

Damage Management Working Group of the Wildlife Society: 

56-63.

The U.S. Department of Agriculture is an equal opportunity employment provider and employer

Major Research Accomplishments:

 WS evaluated the effi cacy of the ONRAB® vaccine for 

use in oral rabies vaccination programs. In an initial 

fi eld trial in West Virginia, ONRAB resulted in the 

highest seroconversion rate in raccoons ever observed for an ORV bait used in the United States , with 

49.4 percent of raccoons showing seroconversion 

post-ORV versus 9.6 percent pre-ORV. Data collected 

from this and non-target studies will aid in the registration of the vaccine for use in the United States.

 WS studies on the availability of water and rabies 

transmission among carnivores indicated that the incidence of encounters between carnivores and cattle 

at water features suggest these locations may lead to 

a higher probability of rabies virus transmission from 

wildlife to livestock.

 WS determined that infrared thermography may be a 

useful noninvasive tool for use in rabies surveillance 

in bats.