MMWR Morb Mortal Wkly Rep. 2011 Mar 11;60(9):276-8.
Japanese encephalitis virus (JEV) is the leading cause of vaccine-preventable encephalitis in Asia and the western Pacific. JEV is maintained in an enzootic cycle involving mosquitoes and amplifying vertebrate hosts, mainly pigs and wading birds. The virus is transmitted to humans primarily by Culex mosquitoes, which breed in flooded rice fields and pools of stagnant water and most often feed outdoors during the evening and night. JEV transmission occurs mainly in rural agricultural areas, but occasional human cases occur in urban areas. Japanese encephalitis (JE) in persons who have traveled or lived overseas is diagnosed infrequently in the United States, with only four cases identified from 1992 (when a JE vaccine was first licensed in the United States) to 2008. This report describes the only cases diagnosed in the United States and reported to CDC since then. The first was a fatal case in a U.S. child who had visited relatives in the Philippines. The other occurred in a refugee who became ill while traveling from Thailand to the United States and whose diagnosis was complicated by concurrent neurocysticercosis. JE should be considered in the differential diagnosis for any patient with an acute neurologic infection who recently has been in a JE-endemic country. Travelers to JE-endemic countries should be advised of the risk for JE and the importance of personal protective measures to prevent mosquito bites. JE vaccine should be considered for travelers who might be at greater risk based on the season, location, and duration of their visit and their planned activities.
日本脑炎病毒（JEV）是亚洲和西太平洋地区可通过疫苗预防的脑炎的主要病因。JEV 通过涉及蚊子和扩增脊椎动物宿主（主要是猪和涉禽）的地方性循环维持。该病毒主要通过库蚊传播给人类，库蚊在洪水泛滥的稻田和死水潭中繁殖，通常在傍晚和夜间在户外觅食。JEV 传播主要发生在农村农业区，但偶尔也会在城市地区发生人类病例。在美国，前往或居住在海外的人罹患日本脑炎（JE）的情况很少见，从 1992 年（美国首次获得 JE 疫苗许可）到 2008 年，仅确诊了 4 例。本报告描述了此后美国仅确诊的病例，并向 CDC 报告。第一例是一名在美国的儿童，他曾前往菲律宾探亲，结果死亡。另一个病例发生在一名从泰国前往美国的难民身上，他的诊断因并发神经囊虫病而变得复杂。对于任何最近去过 JE 流行地区且患有急性神经感染的患者，都应考虑 JE 作为鉴别诊断。应向前往 JE 流行地区的旅行者提供 JE 的风险以及预防蚊虫叮咬的个人保护措施的重要性。应根据旅行者的季节、地点、逗留时间和计划活动，考虑为其接种 JE 疫苗。
