Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR.
Division of Infection and Immunity, University College London, London, UK.
Sci Rep. 2018 May 22;8(1):8018. doi: 10.1038/s41598-018-26333-4.
Japanese encephalitis virus (JEV) is the most commonly identified cause of acute encephalitis syndrome (AES) in Asia. The WHO recommended test is anti-JEV IgM-antibody-capture-enzyme-linked-immunosorbent-assay (JEV MAC-ELISA). However, data suggest this has low positive predictive value, with false positives related to other Flavivirus infections and vaccination. JEV RT-PCR in cerebrospinal fluid (CSF) and/or serum is highly specific, but is rarely positive; 0-25% of patients that fulfil the WHO definition of JE (clinical Acute Encephalitis Syndrome (AES) and JEV MAC-ELISA positive). Testing other body fluids by JEV RT-qPCR may improve the diagnosis. As a pilot study thirty patients admitted to Mahosot Hospital 2014-2017, recruited to the South-East-Asia-Encephalitis study, were tested by JEV MAC-ELISA and two JEV real-time RT-PCR (RT-qPCR) assays (NS2A and NS3). Eleven (36.7%) were JEV MAC-ELISA positive. Available CSF and serum samples of these patients were JEV RT-qPCR negative but 2 (7%) had JEV RNA detected in their throat swabs. JEV RNA was confirmed by re-testing, and sequencing of RT-qPCR products. As the first apparent report of JEV RNA detection in human throat samples, the provides new perspectives on human JEV infection, potentially informing improving JEV detection. We suggest that testing patients' throat swabs for JEV RNA is performed, in combination with molecular and serological CSF and serum investigations, on a larger scale to investigate the epidemiology of the presence of JEV in human throats. Throat swabs are an easy and non-invasive tool that could be rolled out to a wider population to improve knowledge of JEV molecular epidemiology.
日本脑炎病毒（JEV）是亚洲急性脑炎综合征（AES）最常见的病原体。世界卫生组织（WHO）推荐的检测方法是抗 JEV IgM 抗体捕获酶联免疫吸附试验（JEV MAC-ELISA）。然而，数据表明这种方法的阳性预测值较低，假阳性与其他黄病毒感染和疫苗接种有关。JEV 逆转录聚合酶链反应（RT-PCR）在脑脊液（CSF）和/或血清中的特异性很高，但很少呈阳性；符合世界卫生组织（WHO）定义的日本脑炎（JE）的患者中，只有 0-25%的患者 JEV MAC-ELISA 检测结果为阳性。通过 JEV RT-qPCR 检测其他体液可能会提高诊断率。作为一项初步研究，对 2014 年至 2017 年期间在玛霍索医院住院的 30 名符合东南亚脑炎研究条件的患者进行了 JEV MAC-ELISA 和两种 JEV 实时 RT-PCR（RT-qPCR）检测（NS2A 和 NS3）。11 名（36.7%）患者 JEV MAC-ELISA 检测结果为阳性。这些患者的可用 CSF 和血清样本 JEV RT-qPCR 检测结果均为阴性，但 2 名（7%）患者的咽拭子中检测到 JEV RNA。通过重新检测和 RT-qPCR 产物测序证实了 JEV RNA 的存在。这是首次在人类咽拭子中检测到 JEV RNA 的报告，为人类 JEV 感染提供了新的视角，可能有助于改进 JEV 检测。我们建议在更大范围内，通过对患者的咽拭子进行 JEV RNA 检测，结合分子和血清学 CSF 和血清检测，以调查 JEV 在人类咽部分布的流行病学情况。咽拭子是一种简单、非侵入性的工具，可以在更广泛的人群中推广，以提高对 JEV 分子流行病学的认识。
