General epidemiological study of wildlife and domestic animal rabies in Brazil

对从巴西野生动物和家畜中分离到的狂犬病病毒核蛋白基因进行了分子流行病学分析。家畜狂犬病分离株被定义为吸血蝙蝠相关病毒(VRRV)，表明吸血蝙蝠主要将这些病毒传播给家畜。虽然食果蝙蝠有VRRV，但食虫蝙蝠的大多数分离物是独立于VRRV群的。巴西蝙蝠保持着特定物种的RV变异和复杂的相互感染循环。在分子流行病学研究的基础上，建立了RT-PCR结合限制性片段长度多态性(RFLP)分析和多重RT-PCR方法来区分不同动物分离株的RV毒株。多重RT-PCR将被检测的野外分离株分为狐狸、狗、食虫蝙蝠和吸血/食狂暴蝙蝠四个类群。该方法可用于在感染周期特别复杂的巴西对包括人类在内的各种宿主的狂犬病感染源进行分类。为了开发针对最近增加的野生动物来源狂犬病的有效活疫苗，从缺乏整个P基因的疫苗株的cDNA中通过反向遗传学产生了RV缺陷P基因。这种有缺陷的病毒在小鼠身上诱导了对致死性狂犬病感染的保护性免疫，而没有任何致病效应。由于这种基因缺陷病毒可以通过重组野毒株的糖蛋白基因进行有效的遗传修饰，因此它将适用于基于各流行区野毒株抗原性的新型轮状病毒疫苗策略。

Molecular epidemiological analysis of rabies virus (RV) nucleoprotein gene isolated from Brazilian wildlife and domestic animals was performed. Livestock rabies isolates were defined as the vampire bat-related virus(VRRV), showing that vampire bat mainly transmitted these viruses to the livestock. While frugivorous bat had the VRRV, most isolates from insectivorous bat were independent of VRRV group. Brazilian bats maintain species-specific RV variants and complicated jnfectious cycle each other. Amino acid alignment of glycoprotein revealed differences between dog-related rabies virus(DRRV) and VRRV at the positions of antigenic sites and epitopes, suggesting that DRRV and VRRV can be distinguished by differences of antigenicity.Based on the molecular epidemiological studies, RT-PCR along with restriction fragment length polymorphism (RFLP) analysis and multiplex RT-PCR method were established to discriminate and identify the RV reservoirs of field isolates from various animals. Multiplex RT-PCR classified the examined field isolates into four groups, such as fox, dog, insectivorous bat, and vampire/furugivorous bat. This method is useful for the classification of a source of rabies infection in the variety host including human in Brazil which has especially complicated infectious cycle.To develop effective live vaccine against wildlife-derived rabies, which has recently increased, RV deficient P gene was generated by reverse genetics from cDNA of a vaccine strain lacking the entire P gene. The defective virus induced conferred protective immunity against a lethal rabies infection without any pathogenic effects in mice. Since this genetic defective virus can be applied to useful genetic modification by recombining the glycoprotein gene of the field isolate stocks, it would be applicable to the novel RV vaccine strategy based on the antigenicity of field isolates in each prevalent area.