1例特殊的疑似狂犬病死亡病例的实验室检测和确诊

目的采用实验室检测方法确诊一例特殊的疑似狂犬病病例。方法利用荧光抗体(FA)试验、双抗体夹心ELISA和逆转录-聚合酶链式反应(RT-PCR)方法对一例死亡的疑似狂犬病人的脑组织和此脑组织经乳鼠脑内接种传代后的鼠脑组织分别进行检测和分析。结果死亡病人脑组织的直接FA试验和双抗体夹心ELISA检测为阴性,但RT-PCR检测结果为阳性。将该病人脑组织经乳鼠传代后对鼠脑组织用上述三种方法检测的结果均为阳性。对该街毒株的RT-PCR产物中的核蛋白基因序列进行测定,用Mega3.1软件进行分子进化关系分析,证实所分离的街毒株为基因Ⅰ型狂犬病病毒,与以往在该地区所分离的街毒株有较近的遗传关系。结论该病例可确诊为狂犬病死亡病例,其主要和决定性的死因为狂犬病,但并发的肺部感染可能加速了死亡的进程。WHO认为FA技术是狂犬病诊断的金标准,但本病例说明,在某些复杂情况下,只有将多种实验室检测方法联合运用才能确诊狂犬病,而且病毒分离和RT-PCR可能比FA试验更敏感。

Laboratory examination and confirmation for a special case of suspected rabies patient

To make a definite diagnosis for a special case of suspected rabies patient,a series of laboratory examinations including fluorescent antibody assay(FA),ELISA and RT-PCR were carried out to detect the presence of rabies virus in the brain tissues of the suspected rabies patient,as well as in the brain tissues of suckling mice that were inoculated with the brain suspension of the suspected rabies patient.It was demonstrated that the negative results in direct FA assay and the double antibody sandwich ELISA were found,but the result in RT-PCR was positive.In addition,the brain tissues of suckling mice inoculated with brain tissue of the suspected rabies patient showed positive results in these 3 methods of detection mentioned above.As demonstrated by the nucleoprotein gene sequence of the RT-PCR product of the isolated virus and comparison of the phylogenetic relation with Mega 3.1 software,the isolated virus was found to be the gene type 1 rabies virus and this virus showed close relation to the viruses isolated in the same region previously.From these observations,it is concluded that this suspected case can be definitely diagnosed as rabies,and the major and decisive cause for the death of this patient is rabies,but the complicated pulmonary infection would hasten his death.As claimed by WHO,the FA assay is the golden standard for the diagnosis of rabies,but acording to the present study,it is clear that definite diagnosis can only be achieved by the combined use of various laboratory investigations,in which both the virus inoculation and RT-PCR might be more sensitive than SA assay.