确诊与疑似日本脑炎病毒感染临床病例的不相符。

BACKGROUND: Japanese encephalitis (JE) is a notifiable infectious disease in China. Information on every case of JE is reported to the superior health administration department. However, reported cases include both laboratory-confirmed and clinically diagnosed cases. This study aimed to differentiate between clinical and laboratory-confirmed cases of Japanese encephalitis virus (JEV) infection, and improve the accuracy of reported JE cases by analyzing the acute-phase serum and cerebrospinal fluid of all reported JE cases in the Sichuan province from 2012 to 2022. METHODS: All acute-phase serum and/or cerebrospinal fluid samples of the reported JE cases were screened for IgM(ImmunoglobulinM)to JEV using the enzyme-linked immunosorbent assay (ELISA), and the detection of the viral genes of JEV and 9 other pathogens including enterovirus (EV), using reverse transcription PCR was attempted. Epidemiological analyses of JE and non-JE cases based on sex, age, onset time, and geographical distribution were also performed. RESULTS: From 2012 to 2022, 1558 JE cases were reported in the Sichuan province. The results of serological (JEV-specific IgM) and genetic testing for JEV showed that 81% (1262/1558) of the reported cases were confirmed as JEV infection cases (laboratory-confirmed cases). Among the 296 cases of non-JEV infection, 6 viruses were detected in the cerebrospinal fluid in 62 cases, including EV and the Epstein-Barr virus (EBV), constituting 21% (62/296) of all non-JE cases. Among the 62 non-JEV infection cases with confirmed pathogens, infections with EV and EBV included 17 cases each, herpes simplex virus (HSV-1/2) included 14 cases, varicella- zoster virus included 6 cases, mumps virus included 2 cases, and human herpes viruses-6 included 1 case. Additionally, there were five cases involving mixed infections (two cases of EV/EBV, one case of HSV-1/HSV-2, one case of EBV/HSV-1, and one case of EV/herpes viruses-6). The remaining 234 cases were classified as unknown viral encephalitis cases. Our analysis indicated that those aged 0-15 y were the majority of the patients among the 1558 reported JE cases. However, the incidence of laboratory-confirmed JE cases in the >40 y age group has increased in recent years. The temporal distribution of laboratory-confirmed cases of JE revealed that the majority of cases occurred from May to September each year, with the highest incidence in August. CONCLUSION: The results of this study indicate that there is a certain discrepancy between clinically diagnosed and laboratory-confirmed cases of JE. Each reported case should be based on laboratory detection results, which is of great importance in improving the accuracy of case diagnosis and reducing misreporting. Our results are not only important for addressing JE endemic to the Sichuan province, but also provide a valuable reference for the laboratory detection of various notifiable infectious diseases in China and other regions outside China.

背景：日本脑炎（JE）是中国的一种法定传染病。每一例 JE 的信息都要上报上级卫生行政部门。然而，报告的病例包括实验室确诊病例和临床诊断病例。本研究旨在通过分析 2012 年至 2022 年四川省报告的所有 JE 病例的急性期血清和脑脊液，区分日本脑炎病毒（JEV）感染的临床诊断和实验室确诊病例，提高报告 JE 病例的准确性。

方法：使用酶联免疫吸附试验（ELISA）对报告的 JE 病例的所有急性期血清和/或脑脊液样本进行 JEV 特异性 IgM（免疫球蛋白 M）检测，并尝试使用逆转录 PCR 检测 JEV 及其他 9 种病原体（包括肠道病毒[EV]）的病毒基因。还对 JE 和非 JE 病例进行了基于性别、年龄、发病时间和地理分布的流行病学分析。

结果：2012 年至 2022 年，四川省共报告 1558 例 JE 病例。血清学（JEV 特异性 IgM）和 JEV 基因检测结果显示，报告的 1558 例病例中，81%（1262/1558）为 JEV 感染确诊病例（实验室确诊病例）。在 296 例非 JEV 感染病例中，62 例脑脊液中检测到 6 种病毒，包括 EV 和 EBV，占所有非 JE 病例的 21%（62/296）。在 62 例有明确病原体的非 JEV 感染病例中，EV 和 EBV 各有 17 例，单纯疱疹病毒 1/2（HSV-1/2）有 14 例，水痘-带状疱疹病毒有 6 例，腮腺炎病毒有 2 例，人类疱疹病毒 6 型有 1 例。此外，还有 5 例混合感染（2 例 EV/EBV，1 例 HSV-1/HSV-2，1 例 EBV/HSV-1，1 例 EV/疱疹病毒 6 型）。其余 234 例为不明原因病毒性脑炎病例。我们的分析表明，在报告的 1558 例 JE 病例中，0-15 岁的患者居多。然而，近年来>40 岁年龄组的实验室确诊 JE 病例发病率有所增加。JE 实验室确诊病例的时间分布表明，大多数病例发生在每年 5 月至 9 月，8 月发病率最高。

结论：本研究结果表明，JE 的临床诊断和实验室确诊病例之间存在一定差异。每个报告的病例都应基于实验室检测结果，这对于提高病例诊断的准确性和减少误报非常重要。我们的研究结果不仅对解决四川省 JE 流行问题具有重要意义，也为中国和其他地区法定传染病的实验室检测提供了有价值的参考。