Experimental Oral Immunization of Ferret Badgers (Melogale moschata) with a Recombinant Canine Adenovirus Vaccine CAV-2-E3Δ-RGP and an Attenuated Rabies Virus SRV9

Abstract

ABSTRACT:Ferret badgers (Melogale moschata) are a major reservoir of rabies virus in southeastern China. Oral immunization has been shown to be a practical method for wildlife rabies management in Europe and North America. Two groups of 20 ferret badgers were given a single oral dose of a recombinant canine adenovirus-rabies vaccine, CAV-2-E3D-RGP, or an experimental attenuated rabies virus vaccine, SRV9. At 21 days, all ferret badgers had seroconverted, with serum virus-neutralizing antibodies ranging from 0.1 to 4.5 IU/mL. Titers were .0.50 IU/mL (an acceptable level) in 17/20 and 16/20 animals receiving CAV-2-E3D-RGP or SRV9, respectively. The serologic results indicate that the recombinant CAV-2-E3D-RGP is at least as effective as the attenuated rabies virus vaccine. Both may be considered for additional research as oral rabies vaccine candidates for ferret badgers.

Safety, efficacy and immunogenicity evaluation of the SAG2 oral rabies vaccine in Formosan ferret badgers

“…After challenge, there was an antibody increase in SAG2-immunised ferret badgers of around 50-fold, which is much higher than any recorded increase in arctic foxes, red foxes, raccoons, skunks or jackals [ 24 , 26 , 35 , 39 ], even though the seroconversion induced by SAG2 in ferret badgers was not as remarkable as that in raccoon dogs and red foxes. A study of the oral vaccination of Chinese ferret badgers with SRV9 (derived from SAD, an origin shared by SAG2) and CAV-2-E3D-RGP (canine adenovirus harbouring rabies virus glycoprotein) in 10 7.5 plaque-forming units respectively revealed that 16 and 17 out of 20 animals developed positive antibody responses on Day 21, and mean titres were 1–1.6 IU/ml [ 40 ], higher than in this study; hence, ferret badgers do not innately generate low levels of rabies VNA, but a particular immunity activated by SAG2 in ferret badgers and characterised by satisfactory protection independent of humoral immunity induced excellent efficacy. Besides SAG2, this kind of live oral vaccine effect on vaccinated animals with a low seroconversion rate but high protection rate has already been fully documented for another live oral rabies vaccine, the vaccinia-recombinant rabies vaccine [ 41 , 42 ].…”

Genetic Diversity, Evolutionary Dynamics, and Pathogenicity of Ferret Badger Rabies Virus Variants in Mainland China, 2008–2018

“…Nowadays, dog-associated human rabies cases decline rapidly with sufficient production levels for rabies vaccination of domestic dogs and PEP administrations enhanced, FB-associated rabies becomes to be a major threaten factor in some areas of China ( Miao et al, 2021 ). Our study previously study showed that all FB had seroconverted serum, and 80% of the FBs with VNA titers ≥ 0.5 IU/ml either for oral immunization with a recombinant canine adenovirus or SRV9 ( Zhao et al, 2014a ). In this study, we demonstrate that only one dose vaccine either inactivated vaccine, attenuated vaccine or recombined subunit vaccine with intramuscular injection can be used to protect mice from lethal FB rabies virus challenging.…”

“…In 2008, we isolated the first FB rabies virus strain, since then, we continued our surveillance, and collected additional positive samples mainly distributed in Jiangxi and some in Zhejiang province that were isolated from FB. We have conducted laboratory-based surveillance, virus isolation, nucleotide sequencing, and molecular characterization analysis (Zhang et al, 2009(Zhang et al, , 2010Zhao et al, 2014a). Recently, we investigated the temporal dynamics of FB-associated rabies viruses (FB-RABVs) in China based on N sequences from samples collected from 2014 to 2016, results showed that almost all FB isolates until 2013 belonged to the China canine RABV Group II apart two isolated strains in the China canine RABV Group I.…”