Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareily Road, Lucknow 226014, Uttar Pradesh, India.
Prog Neurobiol. 2010 Jun;91(2):108-20. doi: 10.1016/j.pneurobio.2010.01.008. Epub 2010 Feb 2.
Japanese encephalitis (JE) is one of the most important endemic encephalitis in the world especially in Eastern and Southeastern Asia. JE affects over 50,000 patients and results in 15,000 deaths annually. JE virus is a single stranded positive sense RNA virus belonging to family flaviviridae. JE virus is transmitted through a zoonotic cycle between mosquitoes, pigs and water birds. Humans are accidentally infected and are a dead end host because of low level and transient viremia. In the northern region, large epidemics occur during summers whereas in the southern region JE tends to be endemic: cases occur throughout the year with a peak in the rainy season. Occurrence of JE is more closely related to temperature than to humidity. JE is regarded as a disease of children in the endemic areas but in the newly invaded areas, it affects both the adults and children because of the absence of protective antibodies. For every patient of JE, there are large numbers of subclinical cases (25-1000). Symptomatic JEV infection manifests with nonspecific febrile illness, aseptic meningitis or encephalitis. Encephalitis manifests with altered sensorium, seizures and focal neurological deficit. Acute flaccid paralysis may occur due to anterior horn cell involvement. A wide variety of movement disorders especially transient Parkinsonian features and dystonia (limb, axial, orofacial) are reported in 20-60% patients. JE mainly affects thalamus, corpus striatum, brainstem and spinal cord as revealed by MRI and on autopsy studies. Coinfection of JE and cysticercosis occurs because of the important role of pigs in the life cycle of both JEV and cysticercosis. Laboratory diagnosis of JE is by IgM capture ELISA, which has high sensitivity and specificity. In the absence of specific antiviral therapy, JE is managed by symptomatic and supportive therapies and preventive measures. Purified formalin inactivated mouse brain derived vaccine and live attenuated vaccine (SA 14-14-2) are available; the latter is reported to be safe, effective and cheap. The role of Chimeric recombinant attenuated JE vaccine is under investigation. Control of JE is related to the wider issues of hygiene, environment, education and economy.
日本脑炎（JE）是世界上最重要的地方性脑炎之一，特别是在东亚和东南亚。JE 每年影响超过 50000 名患者，导致 15000 人死亡。JE 病毒是一种属于黄病毒科的单链正链 RNA 病毒。JE 病毒通过蚊子、猪和水鸟之间的动物传染病循环传播。人类偶然感染，由于低水平和短暂的病毒血症，成为最终宿主。在北方地区，夏季会发生大规模流行，而在南方地区，JE 倾向于地方性流行：全年都有病例发生，雨季时达到高峰。JE 的发生与温度的关系比与湿度的关系更密切。JE 在流行地区被认为是儿童疾病，但在新入侵地区，由于缺乏保护性抗体，它会影响儿童和成人。每一个 JE 患者，都有大量的亚临床病例（25-1000 个）。有症状的 JEV 感染表现为非特异性发热性疾病、无菌性脑膜炎或脑炎。脑炎表现为意识改变、癫痫发作和局灶性神经功能缺损。由于前角细胞受累，可能会发生急性弛缓性瘫痪。在 20-60%的患者中，报道了广泛的运动障碍，特别是短暂的帕金森特征和肌张力障碍（肢体、轴性、面肌）。MRI 和尸检研究显示，JE 主要影响丘脑、纹状体、脑干和脊髓。JE 和囊尾蚴病的合并感染是由于猪在 JEV 和囊尾蚴病的生命周期中起着重要作用。JE 的实验室诊断是通过 IgM 捕获 ELISA，它具有高灵敏度和特异性。由于没有特定的抗病毒治疗，JE 通过对症和支持治疗以及预防措施进行治疗。已有的疫苗包括用福尔马林灭活的鼠脑衍生疫苗和减毒活疫苗（SA 14-14-2），后者被报道是安全、有效和廉价的。嵌合重组减毒 JE 疫苗的作用正在研究中。JE 的控制与卫生、环境、教育和经济等更广泛的问题有关。
