山东部分乙型脑炎患者中西尼罗病毒感染的研究

Investigation of West Nile Virus infection from Japanese encephalitis patients in Shandong, China

目的 研究山东省是否存在西尼罗病毒（WNV）感染.方法 收集山东省部分地区2013年242例临床诊断为流行性乙型脑炎（JE）患者的样本共计272份（急性期血清和脑脊液214份、恢复期血清58份）.利用逆转录PCR检测急性期样本中乙型脑炎病毒（JEV）和WNV的RNA,并对阳性样本进行病毒分离,用酶联免疫吸附试验（ELISA）检测样本中JEV和WNV的IgM和IgG抗体.对JEV-IgM和WNV-IgM、JEV-IgG和WNV-IgG抗体出现交叉反应的样本进一步检测其抗体效价.将下列两种结果视为WNV感染可疑病例：①两种病毒抗体检测均阳性的样本：抗体效价WNV-IgM/JEV-IgM≥4或WNV-IgG/JEV-IgG≥4者.②WNV-IgM（＋）、JEV-IgM（-）或WNV-IgG（＋）、JEV-IgG（-）的样本.结果 214份急性期样本中有4份JEV RNA的RT-PCR结果（＋）,未扩增出WNVRNA,未分离到病毒.急性期样本中,JEV-IgM阳性率为99.07％（212/214）,WNV-IgM阳性率为35.05％ （75/214）,交叉反应率为34.58％ （74/214）;恢复期样本中,JEV-IgG阳性率为55.17％ （32/58）,WNV-IgG阳性率为46.55％ （27/58）,交叉反应率为为31.03％ （18/58）;WNV感染可疑病例15例.结论 山东部分地区2013年JE患者中可能存在WNV感染病例,但本次研究的结果不能完全支持山东省存在WNV流行的情况,提示在该地区加强JE防控的同时应增加WNV的监测.

Objective To determine whether human infection with West Nile Virus in Shandong province.Methods 272 clinical samples （214 sera and cerebrospinal fluids of acute phase,58 sera of convalescent phase） from 242 patients who were clinically diagnosed as Japanese encephalitis （JE） in parts of Shandong province were collected.RNAs of Japanese encephalitis virus （JEV） and WNV were detected by RT-PCR from acute phase samples,and positive samples were used for virus isolation,IgM and IgG antibodies to JEV and WNV of samples were detected by Enzyme-linked immunosorbent assay （ELISA）.JEV-IgM and WNV-IgM,JEV-IgG and WNV-IgG cross-reacted samples were further detected antibody titers.The following two results were considered as potential WNV infected cases：① Both antibody positive samples：For antibody titers,WNV-IgM/JEV-IgM ≥4 or WNV-IgG/JEV-IgG≥4.②WNV-IgM （＋） and JEV-IgM （-）,or WNV-IgG （＋） and JEV-IgG （-） samples.Results 4 of 214 acute phase samples were positive to JEV RNA,but all samples were negative to WNV RNA by RT-PCR.No virus was isolated from the samples.In acute samples,JEV-IgM positive rate was 99.07% （212/214）,WNV-IgM positive rate was 35.05% （75/214）,cross-reaction rate was 34.58% （74/214）.In convalescent samples,JEV-IgG positive rate was 55.17% （32/58）,WNV-IgG positive rate was 46.55% （32/58）,cross-reaction rate was 31.03% （18/58）.15 patients were considered as potential WNV infection.Conclusions Our study indicated there may be some cases infected with WNV from JE patients in Shandong Province of China,2013,but the results can not fully support the epidemic of WNV in this area,surveillance of WNV should be strengthened meanwhile JE was prevented and controlled.