Journal of Vaccines & Vaccination

New Developments in Oral Rabies Vaccines for Animal Reservoirs

Vos lenin^* Department of Veterinary Clinical Pathology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
^*Correspondence: Vos lenin, Department of Veterinary Clinical Pathology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil, Email:

Received: 26-Apr-2024, Manuscript No. JVV-24-26486; Editor assigned: 29-Apr-2024, Pre QC No. JVV-24-26486 (PQ); Reviewed: 14-May-2024, QC No. JVV-24-26486; Revised: 21-May-2024, Manuscript No. JVV-24-26486 (R) ; Published: 29-May-2024, DOI: 10.35248/2157-7560.24.15.562

Description

Rabies is a deadly viral disease that affects the central nervous system of mammals, including humans. It is predominantly transmitted through the bite of an infected animal. While Post- Exposure Prophylaxis (PEP) is effective for humans, controlling rabies at its source in animal reservoirs remains a critical public health challenge. Oral Rabies Vaccines (ORVs) have emerged as a promising tool to immunize wildlife, thereby reducing the incidence of rabies in both animals and humans.

Wildlife, particularly canids like foxes, raccoons, and skunks, as well as bats, are significant reservoirs of the rabies virus. These animals play a important role in the transmission cycle of the disease. Traditional methods of rabies control, such as isolation and parenteral vaccination, are often impractical and ethically contentious when dealing with wildlife. ORVs provide a feasible and humane alternative by enabling mass vaccination without the need for capturing or handling animals. This approach has proven successful in several regions, contributing to the control and elimination of rabies in wildlife populations.

Mechanisms and development of ORVs

ORVs are designed to be consumed by animals in bait form. The baits contain a vaccine that, when ingested, stimulates an immune response, conferring immunity against the rabies virus. The development of ORVs involves several key steps:

Vaccine strain selection: Selecting an appropriate strain of the rabies virus that is attenuated (weakened) to ensure safety while maintaining immunogenicity is crucial. Commonly used strains include the SAD (Street Alabama Dufferin) and V-RG (Vaccinia- Rabies Glycoprotein) strains.

Bait formulation: The vaccine is incorporated into baits that are attractive to the target species. Bait composition must consider factors such as taste, smell, and durability to withstand environmental conditions until consumed.

Field testing: Extensive field trials are conducted to evaluate the efficacy and safety of the vaccine in the target species. These trials also assess the bait uptake rates and the immune response elicited by the vaccine.

Innovations in ORV technology

Recent developments in ORV technology have focused on improving vaccine efficacy, safety, and delivery mechanisms. Some notable innovations include:

Recombinant vaccines: Recombinant technology has enabled the development of safer and more effective vaccines. The V-RG vaccine, for instance, uses a recombinant vaccinia virus expressing the rabies glycoprotein, providing robust immunity with an excellent safety profile.

Thermostable formulations: Traditional ORVs require cold chain storage, limiting their use in remote areas. New thermostable formulations that remain effective at ambient temperatures are being developed, enhancing the practicality of ORV campaigns in diverse environments.

Automated bait dispensers: Advances in technology have led to the creation of automated bait dispensers, which can be strategically placed to ensure widespread distribution of baits. These dispensers can be programmed to release baits at specific times, reducing human effort and increasing efficiency.

Conclusion

New developments in oral rabies vaccines for animal reservoirs represent a significant advancement in the fight against rabies. Innovations in vaccine technology, bait formulation, and delivery mechanisms have improved the efficacy and feasibility of ORV programs. Despite challenges, the future of ORVs looks promising, with potential to achieve substantial reductions in rabies transmission among wildlife and, consequently, in human populations. Continued research, collaboration, and investment in this field are vital to realizing the full potential of ORVs in global rabies control efforts.