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Since the 1990s, oral rabies vaccination (ORV) has been used successfully to halt the westward spread of the raccoon rabies virus (RV) variant from the eastern continental USA. Elimination of raccoon RV from the eastern USA has proven challenging across targeted raccoon (Procyon lotor) and striped skunk (Mephitis mephitis) populations impacted by raccoon RV. Field trial evaluations of the Ontario Rabies Vaccine Bait (ONRAB) were initiated to expand ORV products available to meet the rabies management goal of raccoon RV elimination. This study describes the continuation of a 2011 trial in West Virginia. Our objective was to evaluate raccoon and skunk response to ORV occurring in West Virginia for an additional two years (2012&ndash, 2013) at 75 baits/km2 followed by three years (2014&ndash, 2016) of evaluation at 300 baits/km2. We measured the change in rabies virus-neutralizing antibody (RVNA) seroprevalence in targeted wildlife populations by comparing levels pre- and post-ORV during each year of study. The increase in bait density from 75/km2 to 300/km2 corresponded to an increase in average post-ORV seroprevalence for raccoon and skunk populations. Raccoon population RVNA levels increased from 53% (300/565, 95% CI: 50&ndash, 57%) to 82.0% (596/727, 95% CI: 79&ndash, 85%) during this study, and skunk population RVNA levels increased from 11% (8/72, 95% CI: 6&ndash, 20%) to 39% (51/130, 95% CI: 31&ndash, 48%). The RVNA seroprevalence pre-ORV demonstrated an increasing trend across study years for both bait densities and species, indicating that multiple years of ORV may be necessary to achieve and maintain RVNA seroprevalence in target wildlife populations for the control and elimination of raccoon RV in the eastern USA.

The statistics of rabies cases in Volyn, Lviv, and Zakarpattia oblasts of Ukraine from 2012 to 2016 were analyzed to establish spatial–temporal distribution of rabies endemic outbreaks and to identify causes of widespread infections among wild and domestic animals. The occurrence of rabies outbreaks in wild and domestic animals in Ukraine was also assessed to determine the effectiveness of oral rabies vaccination (ORV) efforts. According to our analysis, parenteral vaccination of domestic animals and ORV campaigns in foxes have proved unsuccessful in providing a sustainable, long-term reduction in endemic rabies outbreaks. ORV campaigns in foxes were deemed ineffective based on our studies of the endemic rabies outbreaks in Volyn, Lviv, and Zakarpattia oblasts in 2012–2016. The current rabies prevention system (parenteral vaccination) failed to offer protection to domestic animals based on our review of the occurrence of endemic rabies outbreaks in dogs and cats. ORV campaign shortcomings and their causes must be identified in order to provide maximum rabies vaccine coverage for dogs and cats. Altogether, the results presented here provide information that can assist public health agencies to devise more effective disease control plans to curtail the spread of rabies in domestic animals and wildlife in Ukraine.

Bait stations for distribution of oral rabies vaccine baits are designed for rabies management in highly-developed areas where traditional distribution of oral rabies vaccine baits may be difficult. As part of national efforts to contain and eliminate the raccoon (Procyon lotor) variant of the rabies virus (raccoon rabies) in the eastern United States, the United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services program, distributed vaccine baits by bait stations experimentally and operationally in Massachusetts during 2006-present, and in Florida during 2009–2015. In Massachusetts, a rabies virus-neutralizing antibody (RVNA) response of 42.1% for raccoons captured in areas baited with high density bait stations during 2011–2015 was achieved, compared with 46.2% in areas baited by hand, suggesting the continuation of this as a strategy for the oral rabies vaccination (ORV) program there, and for similar locations. Non-target competition for vaccine baits is problematic, regardless of distribution method. In Massachusetts, bait station visitation rates for targeted raccoons and non-target opossums (Didelphis virginiana) were similar (1.18:1) during 2006–2009 (p > 0.05). Bait station modifications for reducing non-target uptake were tested, and in Massachusetts, reduced non-target bait access was achieved with two design alternatives (p < 0.001). However, no difference was noted between the control and these two alternative designs in Florida. Due to ongoing trials of new vaccines and baits, the bait station performance of an adenovirus rabies glycoprotein recombinant vaccine bait, ONRAB® bait (Artemis Technologies, Guelph, ON, Canada) and a vaccinia-rabies glycoprotein recombinant vaccine bait, RABORAL V-RG®bait (Merial Limited, Athens, GA, USA), was compared. While uptake of the ONRAB bait was greater in Massachusetts (p < 0.001) in this limited trial, both types performed equally well in Florida. Since bait station tampering or theft as well as potential human bait contacts has been problematic, performance of camouflaged versus unpainted white bait stations was analyzed in terms of internal temperatures and maintaining a stable bait storage environment. In Massachusetts, camouflaged bait station interiors did not reach higher average temperatures than plain white bait stations in partially- or fully-shaded locations, while in Florida, camouflaged bait stations were significantly warmer in light exposure categories (p < 0.05). As ORV operations expand into more heavily-urbanized areas, bait stations will be increasingly important for vaccine bait distribution, and continued refinements in the strategy will be key to that success.

Economic assessments and modeling studies suggest that these programs yield cost savings and public health benefits., Progressive elimination of rabies in wildlife has been a general strategy in Canada and the United States; common campaign tactics are trap–vaccinate–release (TVR), point infection control (PIC), and oral rabies vaccination (ORV). TVR and PIC are labor intensive and the most expensive tactics per unit area (≈$616/km2 [in 2008 Can$, converted from the reported $450/km2 in 1991 Can$] and ≈$612/km2 [$500/km2 in 1999 Can$], respectively), but these tactics have proven crucial to elimination of raccoon rabies in Canada and to maintenance of ORV zones for preventing the spread of raccoon rabies in the United States. Economic assessments have shown that during rabies epizootics, costs of human postexposure prophylaxis, pet vaccination, public health, and animal control spike. Modeling studies, involving diverse assumptions, have shown that ORV programs can be cost-efficient and yield benefit:cost ratios >1.0.

Efforts to eliminate the raccoon variant of the rabies virus (raccoon rabies) in the eastern United States by USDA, APHIS, Wildlife Services and cooperators have included the distribution of oral rabies vaccine baits from polyvinyl chloride (PVC) bait stations in west-central Florida from 2009 to 2015. Achieving sufficient vaccine bait uptake among urban raccoons is problematic, given limitations on aerial and vehicle-based bait distribution for safety and other reasons. One or three bait stations/km2 were deployed across four 9-km2 sites within rural and urban sites in Pasco and Pinellas Counties, Florida. Based on tetracycline biomarker analysis, bait uptake was only significantly different among the urban (Pinellas County) high and low bait station densities in 2012 (p = 0.0133). Significant differences in RVNA were found between the two bait station densities for both urban 2011 and 2012 samples (p = 0.0054 and p = 0.0031). Landscape differences in terms of urban structure and human population density may modify raccoon travel routes and behavior enough for these differences to emerge in highly urbanized Pinellas County, but not in rural Pasco County. The results suggest that, in urban settings, bait stations deployed at densities of >1/km2 are likely to achieve higher seroprevalence as an index of population immunity critical to successful raccoon rabies control.

Despite perceived challenges to controlling an infectious disease in wildlife, oral rabies vaccination (ORV) of foxes has proved a remarkably successful tool and a prime example of a sophisticated strategy to eliminate disease from wildlife reservoirs. During the past three decades, the implementation of ORV programmes in 24 countries has led to the elimination of fox-mediated rabies from vast areas of Western and Central Europe. In this study, we evaluated the efficiency of 22 European ORV programmes between 1978 and 2010. During this period an area of almost 1.9 million km² was targeted at least once with vaccine baits, with control taking between 5 and 26 years depending upon the country. We examined factors influencing effort required both to control and eliminate fox rabies as well as cost-related issues of these programmes. The proportion of land area ever affected by rabies and an index capturing the size and overlap of successive ORV campaigns were identified as factors having statistically significant effects on the number of campaigns required to both control and eliminate rabies. Repeat comprehensive campaigns that are wholly overlapping much more rapidly eliminate infection and are less costly in the long term. Disproportionally greater effort is required in the final phase of an ORV programme, with a median of 11 additional campaigns required to eliminate disease once incidence has been reduced by 90 per cent. If successive ORV campaigns span the entire affected area, rabies will be eliminated more rapidly than if campaigns are implemented in a less comprehensive manner, therefore reducing ORV expenditure in the longer term. These findings should help improve the planning and implementation of ORV programmes, and facilitate future decision-making by veterinary authorities and policy-makers.

Author(s): Bjorklund, Brian M.; Thomas, Howard H.; Palmiotto, Peter A.; Algeo, Timothy P.; Slate, Dennis; Chipman, Richard B.; Chandler, Monte D.; Wilda, Donald J. | Abstract: USDA APHIS Wildlife Services has been a primary cooperator in the Cape Cod Oral Rabies Vaccination Program (CCORVP) in southeastern Massachusetts since 2001. The CCORVP (1994 - present) was originally designed to reduce the incidence of terrestrial rabies adjacent to the Cape Cod Canal in order to prevent its spread on to peninsular Cape Cod. However, since the barrier breach in 2004, CCORVP is now focused on rabies control in this coastal resort area southeast of Boston, MA. An integral component of wildlife rabies management is oral vaccination with vaccine-laden baits. Consequently, maximizing bait uptake rates is critical to achieving sufficient population immunity to reduce rabies prevalence and achieve control. To that end, knowledge of raccoon food habits, especially at ORV bait delivery times (spring and fall on Cape Cod) is crucial. We undertook a study of raccoon food selection in southeastern Massachusetts to assess the presence of and interest in competing food resources. We collected intact stomachs from raccoons found dead or euthanized for rabies testing within the CCORVP zone during 2006 (n = 33) and 2007 (n = 109) for analysis. Stomach contents were dominated by vegetation (80%), followed by invertebrates (43%), non-food items (41%), vertebrates (35%), and hair (primarily raccoon based on appearance) (15%). Food item occurrence appears to be related to age. We present findings, potential management implications, and suggestions for assessing food use related to rabies control in other locations.

Author(s): Algeo, Timothy P.; Chipman, Richard; Bjorklund, Brian M.; Chandler, Monte D.; Wang, Xingtai; Slate, Dennis; Rupprecht, Charles E. | Abstract: Rabies remains a globally significant zoonotic disease, but rabies control is achievable under certain circumstances. Canine rabies has been eliminated from the U.S.; however, approximately 55,000 humans die annually worldwide from the disease. In the U.S., economic losses continue to be substantial and the risk to humans and domestic animals has not been eliminated. As an example of the complexity of rabies management, we describe a local rabies control program and efforts to restore Cape Cod, MA to terrestrial rabies-free status, after a 2004 oral rabies vaccination (ORV) barrier breach following 10 years of rabies-free status. The emergence of raccoon rabies in southeastern New England in 1992 prompted the U.S. Centers for Disease Control and Prevention, the Tufts Cummings School of Veterinary Medicine, and the Massachusetts Department of Public Health to begin an ORV program to reduce the occurrence of carnivore rabies in an area directly adjacent to the Cape Cod Canal. In 2001, USDA APHIS Wildlife Services began full-time collaboration on the Cape Cod Oral Rabies Vaccination Program (CCORVP) as part of national wildlife rabies control efforts. The primary objective of the CCORVP was to use ORV in tandem with the physical barrier created by the Canal to prevent the spread of rabies to peninsular Cape Cod, a heavily-populated tourist destination southeast of Boston. After an increase in rabies cases within the traditional Cape Cod ORV zone, ORV bait distribution efforts were modified to reduce the risk of rabies spread onto the Cape. In spite of these modifications, raccoon rabies was detected for the first time on peninsular Cape Cod in March 2004. A trap-vaccinate-release campaign, removal of suspect raccoons and skunks, and expanded ORV efforts were unsuccessful in preventing the spread of the virus. Rabies surveillance became the priority of the Cape Cod Rabies Task Force. In 2006, rabies was finally detected at the eastern extremity of the peninsula. In this paper, we summarize ORV efforts, explore possible causes for the spread of raccoon rabies onto the Cape, summarize several small-scale Cape Cod rabies research projects, and suggest a 5-year plan for future Cape Cod rabies controls efforts.

Author(s): Bjorklund, Brian M.; Algeo, Timothy P.; Chandler, Monte D.; Wilda, Donald J.; Slate, Dennis | Abstract: Knowledge of the rate and extent of spread of epizootic diseases is critical to facilitate effective management. Terrestrial rabies was first detected in spring 2004 on Cape Cod Massachusetts, compromising a long-standing ORV zone established from the west side of the Cape Cod Canal to serve as a barrier to raccoon rabies spread onto the Cape. In March 2004, USDA Wildlife Services and local and state cooperators implemented a surveillance program to track the spread of rabies on Cape Cod for planning contingency action strategies aimed at containment and elimination. During 13 months of enhanced rabies surveillance, 198 (167 raccoons and 29 skunks) out of 942 specimens tested positive for rabies. We discuss management implications of these results to the Cape Cod Oral Rabies Vaccination program and to other integrated rabies control programs.

Author(s): Sterner, Ray T. | Abstract: This paper describes issues and concepts relevant to economic modeling of oral rabies vaccination (ORV) campaigns for managing wildlife rabies. Economic models of ORV are mathematical expressions used to predict and draw inferences about the costs and savings likely to be recouped by these rabies management efforts. Costs that are prevented due to ORV campaigns convert to savings. Comparison of campaign duration, bait cost, bait density, and bait distribution data for North American ORV campaigns showed that: 1) campaigns are lengthy, 2) those involving raccoons entail greater bait densities (i.e., related bait costs) and per unit area bait-distribution costs than those involving foxes and coyotes, and 3) all entail “enhanced” surveillance and establishment of maintenance barriers (i.e., deter translocation or reintroduction of new cases) upon completion. Key modeling issues were: model parameterization, ORV cost variables (i.e., bait costs, bait densities, and unit area distribution costs), time horizon, contingency costs, and ORV host specificity.

Author(s): Slate, Dennis; Chipman, Richard B.; Rupprecht, Charles E.; DeLiberto, Thomas | Abstract: Persistence of unique rabies virus variants in a diverse array of terrestrial carnivores and insectivorous bats makes rabies control in the U.S. a complex task. The public health system in the U.S. is effective in keeping human deaths near zero each year in the face of enzootic wildlife rabies, but the annual cost of coexistence with the disease is high, exceeding $300 million. In addition, each year tens of thousands of people are impacted by anxiety, fear, and trauma associated with potential or actual rabies exposure to themselves and their domestic animals. Exclusion, proper storage and disposal of garbage, and removal of problem animals are often effective alternatives to address wildlife rabies threats at specific sites; however, oral rabies vaccination (ORV) is the only currently available technique that shows promise for wildlife rabies control on a broad geographic and species scale. In this paper, we discuss progress toward using ORV to contain specific terrestrial rabies virus variants in the U.S. and planning towards coordinated national efforts to explore the elimination of terrestrial variants of rabies virus in the U.S.