Immunodynamics of field voles

所有生物，无论是植物还是动物，无论是脊椎动物还是无脊椎动物，都受到传染病的困扰，但尽管医学和兽医学取得了进步，我们在很大程度上仍然对传染病对自然(野生动物)种群和群落的影响一无所知。所有生物体都能对感染提供一定程度的抵抗力，但在高等脊椎动物：鸟类和哺乳动物的免疫防御中，这些抵抗力达到了最高水平。这些免疫防御有很多方面：一些提供相当普遍的抵抗力，另一些针对特定类型的感染：例如病毒或寄生虫。即使在一个物种中，免疫防御的总体水平和占主导地位的特定方面也因种群和个体的不同而不同。但我们在很大程度上也对这种差异的程度一无所知，更不用说其原因了。尽管如此，这种“免疫准备”几乎肯定反映了一个人的生活条件(多拥挤、多冷)以及它正在或曾经受到的感染。因此，这个项目将寻求在揭示这些关系方面开辟新的天地：一个人过去和现在的经历，无论是总体上还是与感染有关的，如何反映在这个人的免疫状况中，从而反映在他抵抗感染的能力上。对野生动物传染病的研究本身就受到了寄生虫和病原体与其他“敌人”所不具备的一个特征的极大阻碍：我们只能研究我们专门搜索的寄生虫。与捕食者不同的是，除非我们有意识地寻找它们，否则我们看不到它们。因此，我们研究的寄生虫--只占总数的很小一部分--不是典型的，这是一个持续的危险。然而，绕过这一问题的一种方法不是研究任何特定的病原体，而是研究宿主中表明感染的反应：即处于该项目核心的免疫反应。相反，例如，在研究一种特定的(可能是非典型的)病原体是否影响其宿主的生存时，我们可以问表明“感染”的宿主反应是否与生存下降有关。这也是这个项目的目标。这些相互关联的问题--免疫概况如何反映个人的当前状态？免疫图谱能否作为整体感染的指标？--将在诺森伯兰郡基尔德森林的野生啮齿动物种群中进行研究。我们过去对这些种群有经验，知道它们表现出规律的丰富性波动，这将使我们能够在广泛的密度和条件下研究它们，最大限度地增加我们发现我们所寻找的关系的机会。我们将使用各种新的和更传统的免疫概况测量方法，涵盖其各个方面。我们还将研究各种但数量非常有限的寄生虫--一种病毒、两种细菌和蠕虫--以便利用这个机会将个人的免疫特征与我们知道(也是从过去的经验中)常见的特定感染联系起来。

All organisms, plant or animal, vertebrate or invertebrate, are afflicted by infectious disease, but in spite of medical and veterinary advances, we remain largely ignorant of the effects of infectious disease on natural (wildlife) populations and communities. All organisms are able to offer some level of resistance to infections, but these reach their highest sophistication in the immune defences of the higher vertebrates: birds and mammals. There are many facets to these immune defences: some providing rather general resistance, others directed at particular types of infection: viruses, or parasitic worms, for example. Even within a species, the overall level of immune defence, and the particular facet that dominates, varies from population to population and from individual to individual. But we are largely ignorant, too, of even the extent of this variation, to say nothing of its causes. Nonetheless, such 'immune-preparedness' almost certainly reflects both the conditions in which an individual is living (how crowded, how cold) and the infections it is, or has been, subjected to. This project, then, will seek to break new ground in uncovering these relationships: how the past and present experiences of an individual, both in general and with regard to infection, are reflected in that individual's immune profile and hence in its ability to fight infection. The study of infectious disease in wildlife has itself been hindered greatly by a characteristic that parasites and pathogens do not share with other 'enemies': we can only study parasites that we specifically search for. Unlike predators, say, we cannot see them unless we consciously look for them. Hence, there is a constant danger that the parasites we do study - only a very small proportion of the total - are not typical. One way around this, however, would be not to study any particular pathogen, but to study responses in the host that indicate infection 'in general': that is, the immune responses that are at the heart of this project. Instead, for example, of studying whether a particular (perhaps atypical) pathogen affects the survival of its host, we can ask whether host responses that indicate 'infection' are associated with reduced survival. This, too, is the objective of this project. These linked questions - how does the immune profile reflect the current state of an individual? and can the immune profile be used as a proxy for the totality of infections? - will be studied in a population of wild rodents, field voles, in Kielder Forest, Northumberland. We have past experience with these populations and know that they exhibit regular fluctuiations in abundance that will allow us to study them at a wide range of densities and conditions, maximising our chances of uncovering the relationships we seek. We will use a variety of measures of the immune profile, newer and more conventional, covering its various facets. We will also study a varied but very limited number of parasites - a virus, two bacteria and helminth worms - in order to utilise the opportunity to relate the immune profiles of individuals to specific infections that we know (also from past experience) to be common.