RABORAL V-RG® is an oral rabies vaccine bait that contains an attenuated (“modified-live”) recombinant vaccinia virus vector vaccine expressing the rabies virus glycoprotein gene (V-RG). Approximately 250 million doses have been distributed globally since 1987 without any reports of adverse reactions in wildlife or domestic animals since the first licensed recombinant oral rabies vaccine (ORV) was released into the environment to immunize wildlife populations against rabies. V-RG is genetically stable, is not detected in the oral cavity beyond 48 h after ingestion, is not shed by vaccinates into the environment, and has been tested for thermostability under a range of laboratory and field conditions. Safety of V-RG has been evaluated in over 50 vertebrate species, including non-human primates, with no adverse effects observed regardless of route or dose. Immunogenicity and efficacy have been demonstrated under laboratory and field conditions in multiple target species (including fox, raccoon, coyote, skunk, raccoon dog, and jackal). The liquid vaccine is packaged inside edible baits (i.e., RABORAL V-RG, the vaccine-bait product) which are distributed into wildlife habitats for consumption by target species. Field application of RABORAL V-RG has contributed to the elimination of wildlife rabies from three European countries (Belgium, France and Luxembourg) and of the dog/coyote rabies virus variant from the United States of America (USA). An oral rabies vaccination program in west-central Texas has essentially eliminated the gray fox rabies virus variant from Texas with the last case reported in a cow during 2009. A long-term ORV barrier program in the USA using RABORAL V-RG is preventing substantial geographic expansion of the raccoon rabies virus variant. RABORAL V-RG has also been used to control wildlife rabies in Israel for more than a decade. This paper: (1) reviews the development and historical use of RABORAL V-RG; (2) highlights wildlife rabies control programs using the vaccine in multiple species and countries; and (3) discusses current and future challenges faced by programs seeking to control or eliminate wildlife rabies.
As a neglected zoonotic disease, rabies causes approximately 5.9 × 104 human deaths annually, primarily affecting low- and middle-income countries in Asia and Africa. In those regions, insufficient surveillance is hampering adequate medical intervention and is driving the vicious cycle of neglect. Where resources to provide laboratory disease confirmation are limited, there is a need for user-friendly and low-cost reliable diagnostic tools that do not rely on specialized laboratory facilities. Lateral flow devices (LFD) offer an alternative to conventional diagnostic methods and may strengthen control efforts in low-resource settings. Five different commercially available LFDs were compared in a multi-centered study with respect to their diagnostic sensitivity and their agreement with standard rabies diagnostic techniques. Our evaluation was conducted by several international reference laboratories using a broad panel of samples. The overall sensitivities ranged from 0% up to 62%, depending on the LFD manufacturer, with substantial variation between the different laboratories. Samples with high antigen content and high relative viral load tended to test positive more often in the Anigen/Bionote test, the latter being the one with the best performance. Still, the overall unsatisfactory findings corroborate a previous study and indicate a persistent lack of appropriate test validation and quality control. At present, the tested kits are not suitable for in-field use for rabies diagnosis, especially not for suspect animals where human contact has been identified, as an incorrect negative diagnosis may result in human casualties. This study points out the discrepancy between the enormous need for such a diagnostic tool on the one hand, and on the other hand, a number of already existing tests that are not yet ready for use.
SUMMARY: Between 1979 and 2000, foxes constituted the main reservoir of rabies in the Northern regions of Israel. Following the implementation of the fox-targeted oral vaccination programme (ORV) in 1998, rabies was eradicated from this area. Subsequently during 2004–2007, the biological and molecular characterization of the rabies isolates showed that stray dogs emerged as the main animal reservoir in Northern Israel while lower numbers of cases were reported in domestic animals. The virus isolates from foxes and dogs differed, in their molecular characterization, suggesting two distinct separate lineages. The transition from fox-mediated rabies to dog-mediated rabies is of great concern to public health because of the close contact between dogs and the human population.
Rabies is a fatal zoonotic disease affecting all mammalian species. It is caused by the rabies virus and is prevalent worldwide. Horses are not commonly infected with rabies but their vaccination is recommended due to the potential zoonotic risk. This study aimed to evaluate the duration of immunity following rabies vaccination in horses. A total of 126 serum samples were collected from 93 horses, vaccinated 6 to 91 months before sampling. Rabies-virus-neutralizing antibody (RVNA) levels were evaluated using the Rabies Fluorescent Focus Inhibition Test (RFFIT). A protective RVNA titer of above 0.5 IU/mL was found in 112 (88.9%) of the samples and 84 (90.3%) of the horses. Antibody titers declined over time (rho = −0.271, p = 0.002); however, there was no significant difference in antibody titers or the prevalence of unprotected horses between the time intervals following vaccination. Purebred horses had lower antibody titers (p = 0.024). The response to booster vaccination was inspected in ten horses, and increased antibody titers were found in eight of them. The results of this study demonstrate the prolonged persistence of protective immunity in horses following rabies vaccination, in some cases, for up to eight years. Therefore, the current annual vaccination strategy should be re-evaluated. A rate of 9.7% of poor responders should be considered from an epidemiological perspective in order to minimize the risk of emergence of the disease.