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目的了解小鼠脑脊髓炎病毒(TMEV)自然感染情况,探究人工感染TMEV小鼠体内各脏器组织中病毒分布及血清抗体变化。方法采用酶联免疫吸附试验(ELISA)和荧光定量RT-PCR(qRT-PCR)检测方法对2010年~2015年广东地区采集的SPF级小鼠、开放环境饲养的小鼠以及野生褐家鼠临床样本进行TMEV检测。36只ICR小鼠经脑内接种TMEV BeAn病毒,每天观察动物的临床症状,在接种第0、3、7、10、17、21、31、39、46天每个时间点分别对3只动物安乐死,剖检并取血清和组织脏器样本进行TMEV检测。结果 SPF级小鼠TMEV抗体阳性率为5.29%(n=2834),核酸阳性率为27.27%(n=457);开放环境饲养的小鼠的抗体和核酸阳性率分别为71.95%(n=82)和53.66%(n=82);野生褐家鼠中核酸阳性率为25.93%(n=27)。TMEV阳性小鼠中仅有两只小鼠表现有明显的临床症状。盲肠内容物、粪便和脑是qRT-PCR检测的最佳选择样本。ICR小鼠脑内接种TMEV BeAn病毒后第3 d可在脑、心脏、肝脏、肺脏和胃中检测到病毒核酸,脾脏、肾脏和盲肠中未检测到病毒核酸。肝脏、心脏、肺脏和胃中的病毒在接种后第10天已完全清除,脑中的病毒一直持续存在到第46天试验结束。小鼠感染后第7天可以检测到抗体,随后抗体水平逐渐升高,接种后17 d抗体阳性率达100%,并一直到46 d都可以维持较高的抗体水平。人工感染小鼠呈隐性感染,临床上并未表现明显症状和眼观病理变化。结论广东地区实验小鼠和野生褐家鼠均存在TMEV感染,且感染率较高。小鼠接种TMEV BeAn毒株后呈隐性感染,感染小鼠第7天可以产生抗体且持续存在。病毒在感染小鼠肝脏、心脏、肺脏和胃中短时间存在,而在脑中长期存在。qRT-PCR与ELISA两种检测方法具有较好的一致性,qRT-PCR检测方法可作为实验动物国家标准的有力补充。
Objective To understand the natural infection of mouse encephalomyelitis virus (TMEV) and investigate the distribution of virus and the changes of serum antibody in various tissues of TMEV mice. Methods SPF mice collected in Guangdong from 2010 to 2015, mice raised in the open environment, and wild brown rodents were studied by ELISA and qRT-PCR. Samples for TMEV testing. Thirty-six ICR mice were inoculated intranasally with TMEV BeAn virus, and the clinical symptoms of animals were observed daily. Three animals were respectively inoculated on the 0,3,7,10,17,21,31,39,46 day after inoculation Euthanasia, necropsy and serum and tissue samples taken for TMEV detection. Results The positive rate of TMEV antibody in SPF mice was 5.29% (n = 2834) and the positive rate of nucleic acid was 27.27% (n = 457). The positive rate of antibody and nucleic acid in mice fed SPF was 71.95% (n = 82) ) And 53.66% (n = 82) respectively. The positive rate of nucleic acid in wild brown rodent was 25.93% (n = 27). Only two mice in TMEV-positive mice showed significant clinical symptoms. Cecal contents, faeces and brain are the best choice for qRT-PCR detection. On day 3 after virus inoculation with TMEV BeAn virus in ICR mice, no detectable viral nucleic acid was detected in brain, heart, liver, lung and stomach in viral nucleic acid, spleen, kidney and cecum. The virus in the liver, heart, lungs and stomach was completely eliminated on the 10th day after inoculation, and the virus in the brain persisted until the end of the experiment on the 46th day. Antibody was detected on the 7th day after infection in mice, then the level of antibody was gradually increased. The positive rate of antibody reached 100% on the 17th day after inoculation, and the level of antibody could be maintained up to 46 days. Artificially infected mice were latent infection, clinically did not show obvious symptoms and eye pathological changes. Conclusion There are TMEV infection in experimental mice and wild brown house mice in Guangdong area, and the infection rate is high. The mice inoculated with TMEV BeAn strain showed a recessive infection. Antibody was persisted in the infected mice on the 7th day. The virus exists in the liver, heart, lungs and stomach of infected mice for a short period of time, but exists in the brain for a long time. qRT-PCR and ELISA detection methods have good consistency, qRT-PCR detection method can be used as a powerful supplement to the national standards of experimental animals.