Selvey Linda A, Dailey Lynne, Lindsay Michael, Armstrong Paul, Tobin Sean, Koehler Ann P, Markey Peter G, Smith David W
School of Public Health, Curtin University, Perth, Western Australia, Australia.
Independent consultant, Perth, Western Australia, Australia.
PLoS Negl Trop Dis. 2014 Jan 23;8(1):e2656. doi: 10.1371/journal.pntd.0002656. eCollection 2014.
Murray Valley encephalitis virus (MVEV) is the most serious of the endemic arboviruses in Australia. It was responsible for six known large outbreaks of encephalitis in south-eastern Australia in the 1900s, with the last comprising 58 cases in 1974. Since then MVEV clinical cases have been largely confined to the western and central parts of northern Australia. In 2011, high-level MVEV activity occurred in south-eastern Australia for the first time since 1974, accompanied by unusually heavy seasonal MVEV activity in northern Australia. This resulted in 17 confirmed cases of MVEV disease across Australia. Record wet season rainfall was recorded in many areas of Australia in the summer and autumn of 2011. This was associated with significant flooding and increased numbers of the mosquito vector and subsequent MVEV activity. This paper documents the outbreak and adds to our knowledge about disease outcomes, epidemiology of disease and the link between the MVEV activity and environmental factors. Clinical and demographic information from the 17 reported cases was obtained. Cases or family members were interviewed about their activities and location during the incubation period. In contrast to outbreaks prior to 2000, the majority of cases were non-Aboriginal adults, and almost half (40%) of the cases acquired MVEV outside their area of residence. All but two cases occurred in areas of known MVEV activity. This outbreak continues to reflect a change in the demographic pattern of human cases of encephalitic MVEV over the last 20 years. In northern Australia, this is associated with the increasing numbers of non-Aboriginal workers and tourists living and travelling in endemic and epidemic areas, and also identifies an association with activities that lead to high mosquito exposure. This outbreak demonstrates that there is an ongoing risk of MVEV encephalitis to the heavily populated areas of south-eastern Australia.
墨累谷脑炎病毒（MVEV）是澳大利亚地方性虫媒病毒中最为严重的一种。在20世纪，它曾导致澳大利亚东南部发生6次已知的大规模脑炎疫情，最后一次疫情发生在1974年，共有58例病例。自那时起，MVEV临床病例主要局限于澳大利亚北部的西部和中部地区。2011年，自1974年以来澳大利亚东南部首次出现高水平的MVEV活动，同时澳大利亚北部还出现了异常严重的季节性MVEV活动。这导致澳大利亚各地共确诊17例MVEV疾病病例。2011年夏秋两季，澳大利亚许多地区记录到创纪录的雨季降雨量。这与严重洪灾、蚊虫媒介数量增加以及随后的MVEV活动增加有关。本文记录了此次疫情，并增加了我们对疾病结局、疾病流行病学以及MVEV活动与环境因素之间联系的认识。获取了17例报告病例的临床和人口统计学信息。对病例或其家庭成员进行了访谈，了解他们在潜伏期的活动和地点。与2000年之前的疫情不同，大多数病例是非原住民成年人，几乎一半（40%）的病例在其居住地区以外感染了MVEV。除两例病例外，所有病例均发生在已知有MVEV活动的地区。此次疫情继续反映出过去20年中MVEV脑炎人类病例人口统计学模式的变化。在澳大利亚北部，这与生活和旅行于地方性和流行地区的非原住民工人和游客数量增加有关，同时也确定了与导致高蚊虫暴露的活动之间的关联。此次疫情表明，澳大利亚东南部人口密集地区持续面临MVEV脑炎的风险。
