Yang Dong-Kun, Kim Choong-Sik, Kim Jin, Yeo Jongsup, Yoo Sungsik, Won Hokeun, Lee Ju-Yeon, Lee Hye Jeong, Cho Yun Sang
Viral Disease Division, Animal and Plant Quarantine Agency, Ministry of Agriculture, Food and Rural Affairs, Gimcheon, Korea.
ChoongAng Vaccine Laboratories Co., Ltd. (CAVAC), Daejeon, Korea.
Clin Exp Vaccine Res. 2025 Apr;14(2):149-156. doi: 10.7774/cevr.2025.14.e13. Epub 2025 Mar 24.
Rabies is a deadly zoonotic disease affecting many mammals, including humans. Oral rabies bait vaccines induce an immune response without direct inoculation, and are crucial for controlling rabies in wildlife. This study evaluated the safety and immunogenicity of a new rabies bait vaccine containing a recombinant rabies virus expressing green fluorescent protein (ERAGS-GFP) in wild raccoon dogs.
To confirm the safety of the ERAGS-GFP vaccine, reversion to virulence was evaluated in 1-day-old suckling mice. The uptake, minimum effective dose, and immunogenicity of the bait vaccine were assessed in raccoon dogs, as was the persistence of post-vaccine immunity. Serum rabies virus neutralizing antibody (VNA) titers were measured using fluorescent antibody virus neutralization.
No adverse effects were noted in mice, guinea pigs, dogs, or raccoon dogs administered the ERAGS-GFP vaccine orally during the test period. The glycoprotein gene of the ERAGS-GFP strain remained unchanged after five reverse passages in 1-day-old mice. Uptake of the bait vaccine was 75.8% in raccoon dogs. The minimum effective dose was at least 10 TCID/mL. Forty-three raccoon dogs administered the ERAGS-GFP bait vaccine developed an average VNA titer of 4.23 IU/mL 28 days post-administration. Protective antibody levels were maintained for 4 months.
The ERAGS-GFP bait vaccine showed high uptake and strong immunogenicity in raccoon dogs, and protective antibody levels were maintained for at least 4 months. These results indicate the vaccine's potential for effective rabies control in wildlife, which can reduce the risk of transmission to humans and domestic animals.
狂犬病是一种致命的人畜共患病，可影响包括人类在内的许多哺乳动物。口服狂犬病诱饵疫苗无需直接接种即可诱导免疫反应，对控制野生动物狂犬病至关重要。本研究评估了一种含有表达绿色荧光蛋白的重组狂犬病病毒的新型狂犬病诱饵疫苗（ERAGS-GFP）在野生貉中的安全性和免疫原性。
为确认ERAGS-GFP疫苗的安全性，在1日龄乳鼠中评估其毒力返强情况。在貉中评估诱饵疫苗的摄取、最小有效剂量和免疫原性，以及疫苗接种后免疫力的持久性。使用荧光抗体病毒中和法测量血清狂犬病病毒中和抗体（VNA）滴度。
在试验期间，口服ERAGS-GFP疫苗的小鼠、豚鼠、犬或貉均未出现不良反应。ERAGS-GFP株的糖蛋白基因在1日龄小鼠中连续传代5次后未发生变化。貉对诱饵疫苗的摄取率为75.8%。最小有效剂量至少为10 TCID/mL。43只接种ERAGS-GFP诱饵疫苗的貉在接种后28天的平均VNA滴度为4.23 IU/mL。保护性抗体水平维持了4个月。
ERAGS-GFP诱饵疫苗在貉中显示出高摄取率和强免疫原性，保护性抗体水平至少维持4个月。这些结果表明该疫苗在有效控制野生动物狂犬病方面具有潜力，可降低传播给人类和家畜的风险。
