汉坦病毒和恙虫病东方体复合感染的实验研究

Experimental study on the co-infection of Hantavirus and Orientia tsutsugamushi

目的了解汉坦病毒(HV)和恙虫病东方体(Ot)在宿主体内能否共生及其共生特征。方法采用HV和Ot先后交替、重复感染实验鼠,20 d后取鼠脏器切片和刮片用IFAT和Giemsa染色观察其感染率和脏器分布;并用Vero-E6细胞体外培养法研究HV、Ot在宿主细胞内的共生特征。用RT-PCR和PCR进行基因鉴定。结果HV和Ot先后交替、重复感染的各组实验鼠中,均可发现两种病原体的复合感染,其中HV和Ot单纯感染组的阳性率均显著高于HV、Ot先后和同时感染组。5组感染Vero-E6细胞培养检测结果发现:先后、同时和单纯实验感染的5组细胞中,HV和Ot先后、同时接种感染组在细胞传至第3代时检测均见有HV和Ot的双重感染,阳性率随传代次数增加而增加。而HV和Ot单纯分别感染组细胞传第2代时即可检测到HV和Ot,阳性率亦随传代次数的增加而增加。在传代培养中单纯感染组的阳性率均显著高于先后和同时感染组。用PCR和RT-PCR进行了基因鉴定得到一致的结果。结论研究结果提示HV和Ot可重复感染宿主动物,在同一宿主细胞内的感染初期有相互抑制作用,这对HV和Ot的流行病学有一定的理论意义。

To determine whether Hantavirus（HV） and Orientia tsutsugarnushi（Ot） could co-exist in their hosts and to investigate the characteristics of the co-infection, mice were infected alternately or repeatedly with HV and Ot, and 20 days later, the slices and printing smears of viscera of mice were examined with IFAT and Giemsa staining to observe the infection rate and the organ distributions of HV and Ot. In addition, the characteristics of co-infection was observed in vitro by inoculating HV and Ot singly, simultaneously or successively into Vero-E6 cells, and the presence of genes of HV and Ot were identified by RT-PCR and PCR. The experimental results showed that co-infection of HV and Ot did exist in those groups of mice infected alternately or repeatedly with these two pathogens, in which the infection rate of the singly infected group of mice was significantly higher than the simultaneously or successively infected groups of mice. The results of 5 experiment groups of the infected Vero E-6 cells showed that HV and Ot were both positive in the Vero E-6 cells passaged through two times, and the positive rate was increased with the passaging times for HV and Ot infected simultaneously or successively. However, in the groups of mice infected with HV and Ot separately, genes of HV or Ot could be detected in the infected Vero E-6 cells passaged only for one time, so the positive rate increased following with the times of passages. All together, the positive rate was higher in the single infected group of mice than those infected simultaneously or successively. It is concluded that co-infection of HV and Ot does exist in the present experiment condition, and these two pathogens can inhibit each other in the initial infection stage.