Immunogenicity and Safety of Recombinant Rabies Viruses Used for Oral Vaccination of Stray Dogs and Wildlife

Abstract

Rabies is a zoonotic disease and stray dogs, wild carnivores and bats are the natural reservoirs of rabies. Oral immunization with live vaccines is the only practical approach to eradicate rabies in free ranging terrestrial animals. We have developed the double glycoprotein (G) rabies virus (RV) variant SPBNGAS-GAS that has great promise to be used as a live-attenuated vaccine. Oral immunization of rodents and several target animal species with this double G RV variant resulted in the induction of protective immunity, superior to that induced by a single RV G variant (SPBNGAS). The high oral efficacy of SPBNGAS-GAS is likely because of its increased ability to infect monocytes or immature dendritic cells (DCs), thereby inducing their conversion into mature DCs. Furthermore, infection of DCs with the double G variant resulted in a strong up-regulation of the expression of genes related to the NFjB signalling pathway including IFN-α and IFN-β, which might underlie the protection conferred by this live RV vaccine. A potential problem associated with the use of live RVs for oral vaccination could rest in the possibility of reversion to the pathogenic phenotype because of the high mutation rate characteristic for all RNA viruses. In this respect, the presence of a second non-pathogenic G gene decreases considerably the risk of reversion to the pathogenic phenotype because a nonpathogenic G is dominant over a pathogenic G in determining the pathogenicity of the double G RV variant. Because of its excellent efficacy and safety, the SPBNGAS-GAS vaccine may provide a distinct advantage over other live RV vaccine in its ability to vaccinate a broad range of mammalian species.

A Novel Rabies Vaccine Based on a Recombinant Parainfluenza Virus 5 Expressing Rabies Virus Glycoprotein

“…immunization provided the best protection for rPIV5-RV-G, to vaccinate stray dogs or wild animals, oral immunization will be the best approach. Oral vaccine has advantages over traditional vaccines, such as its ease of use, compatibility with mass immunization campaigns, and ability to reach hard-to-reach species (40). Although only half of the mice in our study were protected with one-dose vaccination, the result is encouraging.…”

Raccoons in Europe: disease hazards due to the establishment of an invasive species

“…Wild carnivores are natural reservoirs (Faber et al 2009) and are responsible for the maintenance of the infectious cycle. Despite most of the wildlife species carry their own rabies variant, the spillover to other species is possible (Lackay et al 2008;Wang et al 2009).…”

Oral Vaccination of Captive Small Indian Mongoose (Herpestes auropunctatus) against Rabies

“…Animals were sedated with 5 mg ketamine (Ketamin, WDT, Garbsen, Germany) and 0.1 mg Medetomidine (DomitorH, Janssen Animal Health, Neuss, Germany). Two of the six sedated and relocated animals received 1.0 mL by direct oral instillation with SPBN GAS-GAS (10 8.5 focus-forming units (FFU)/ mL), a highly attenuated live rabies virus construct developed using reverse genetics (Faber et al, 2009). The other four animals were offered the selected vaccine bait 1 wk after relocation, which contained approximately 0.6 mL SPBN GASGAS (10 8.5 FFU/ml).…”