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的狂犬病病毒（RV）核蛋白基因进行了分子流行病学分析。牲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牲畜。食果蝙蝠分离到VRRV，而食虫蝙蝠分离到的大多数菌株与VRRV群无关。巴西蝙蝠保持物种特异性RV变体和复杂的相互感染循环。犬相关狂犬病病毒（DRRV）和VRRV糖蛋白的氨基酸序列比对结果显示，DRRV和VRRV在抗原位点和表位上存在差异，提示DRRV和VRRV可以通过抗原性的差异来区分。RT-PCR沿着限制性片段长度多态性（RFLP）分析和多重RT-PCR。建立了区分和鉴定不同动物源RV野毒株宿主的PCR方法。多重RT-PCR将所检测的野毒株分为狐、犬、食虫蝙蝠和吸血/食腐蝙蝠4类。该方法可用于包括巴西人在内的各种宿主中狂犬病感染源的分类，巴西人具有特别复杂的感染周期。为了开发针对最近增加的野生动物来源的狂犬病的有效活疫苗，通过反向遗传学从缺乏整个P基因的疫苗株的cDNA产生RV缺陷P基因。所诱导的缺陷型病毒在小鼠中赋予针对致死性狂犬病感染的保护性免疫，而没有任何致病作用。由于这种遗传缺陷病毒可以通过重组田间分离株的糖蛋白基因来进行有用的遗传修饰，因此它将适用于基于每个流行地区田间分离株抗原性的新型RV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.