Ljungan Virus - an undetected but dangerous zoonotic agent

1998年，Nikraasson和其他人报告说，瑞典有三种人类疾病的发病率，即人类心肌炎、糖尿病和格林-巴利综合征，这三种疾病的发生率随着银行田鼠3-4年的丰收周期而变化。随后，从瑞典糖尿病银行田鼠体内分离到一种新病毒--永干病毒(Ljugan Virus，LV)。在丹麦和美国的野生田鼠中也存在LV，最近在瑞典北部的其他几种野生田鼠和旅鼠中分离出LV，并报告了心肌炎和临床糖尿病。利物浦正在进行的一项研究一直在关注野生啮齿动物的一系列感染(但不是LV)，特别是生活在英格兰和苏格兰边境基尔德森林的种群。尼克拉森访问了利物浦，并检查了从基尔德种群中移走的田鼠。初步分析为这些人群中存在LV提供了一个强有力的初步证据。1型糖尿病在儿童和年轻人中的分布还不是很清楚，尽管遗传和环境因素都可能参与其中。许多研究表明，感染和/或免疫反应可能起作用。时空聚集性(在有限的时间内在小的地理位置观察到的病例数量过多)尤其提示感染。几项研究已经确定了儿童糖尿病的时空聚集现象。这个拟议的项目将：1)调查基尔德种群和附近的其他啮齿动物物种(包括家鼠周围的老鼠)，以便开始绘制英国啮齿动物的LV(和可能的人类风险)图；以及2)分析啮齿动物种群区域的人类流行病学数据库，以寻找1型糖尿病发病率与啮齿动物数量或活动指标之间的空间(区域)或时间上的相关性；如果这些试点研究在其中一个方面或特别是在两个方面(没有证实永干病毒和/或公共卫生记录中没有公开的模式)得出负面结果，那么在瑞典观察到的模式不太可能也适用于英国，对这一主题的研究可以被认为是低优先级的。但如果其中一项研究或特别是两项研究都提供了积极的结果，那么永干病毒有可能成为英国最重要的野生动物人畜共患病，进一步的工作将是必不可少的。

In 1998, Niklasson and others reported that the incidence of three human diseases in Sweden, human myocarditis, diabetes and Guillain-Barre syndrome, varied with the 3-4 year abundance cycles of the bank vole. Subsequently, a new virus, Ljungan virus (LV) was isolated from Swedish diabetic bank voles. LV is also present in wild voles in Denmark and the USA and has recently been isolated, and myocarditis and clinical diabetes reported, in several other species of wild voles and lemmings in northern Sweden. An on-going study at Liverpool has been looking at a range of infections (but not LV) in wild rodents, focusing especially on populations living in Kielder Forest, on the English-Scottish border. Niklasson has visited Liverpool and examined voles removed from the Kielder populations. Preliminary analyses have provided a strong prima facie case for the presence of LV in these populations. The distribution of type 1 diabetes amongst children and young adults is not well understood, although both genetic and environmental factors are likely to be involved. A number of studies suggest a possible role for infections and/or immunological responses. Space-time clustering (excess numbers of cases observed within small geographical locations for limited periods of time) is especially suggestive of an infection. Several studies have identified space-time clustering in childhood diabetes. This proposed project would: 1) survey the Kielder populations and those of other rodent species nearby (including peri-domestic rats and mice) in order to initiate a mapping of LV (and possible human risk) in UK rodents; and 2) analyse human epidemiological data bases in the region of the rodent populations to seek correlations either spatially (regionally) or temporally between incidences of type 1 diabetes and measures of rodent abundance or activity; If these pilot studies provide negative results in either or especially both respects (no confirmation of Ljungan virus and/or no overt patterns in the public health records), then it will be unlikely that patterns observed in Sweden also apply in the UK, and research on this topic can be considered of low priority. But if either or especially both studies provide positive results, then Ljungan virus has the potential to become the most important wildlife zoonosis in the UK and further work will be essential.