Immunodynamics of field voles

所有生物体，植物或动物，脊椎动物或无脊椎动物，都受到传染病的折磨，但尽管医学和兽医学的进步，我们仍然在很大程度上忽视了传染病对自然（野生动物）种群和社区的影响。所有生物都能对感染提供一定程度的抵抗力，但这些抵抗力在高等脊椎动物（鸟类和哺乳动物）的免疫防御中达到最高水平。这些免疫防御有许多方面：一些提供相当普遍的抵抗力，另一些针对特定类型的感染：例如病毒或寄生蠕虫。即使在一个物种内，免疫防御的总体水平，以及占主导地位的特定方面，也因种群和个体而异。但是，我们在很大程度上也不知道这种变化的程度，更不用说它的原因了。尽管如此，这种“免疫准备”几乎肯定反映了一个人生活的条件（多么拥挤，多么寒冷）以及它正在或已经受到的感染。因此，该项目将寻求在揭示这些关系方面开辟新的领域：一个人过去和现在的经历，无论是一般的还是关于感染的，如何反映在这个人的免疫状况中，从而反映在其对抗感染的能力中。野生动物中传染病的研究本身就受到了寄生虫和病原体不与其他“敌人”共享的特性的极大阻碍：我们只能研究我们专门寻找的寄生虫。与捕食者不同，我们看不到它们，除非我们有意识地寻找它们。因此，我们所研究的寄生虫--只占总数的很小一部分--并不典型，这是一个持续的危险。然而，解决这个问题的一种方法是不研究任何特定的病原体，而是研究宿主中表明感染的“一般”反应：也就是说，免疫反应是这个项目的核心。例如，在研究一种特定的（也许是非典型的）病原体是否会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率降低有关。这也是这个项目的目标。这些相关的问题-免疫概况如何反映个人的当前状态？免疫谱是否可以作为感染总数的代表？- 将在诺森伯兰郡基尔德森林的一群野生啮齿动物，田鼠中进行研究。我们有过去的经验与这些人口，并知道他们表现出丰富的定期波动，这将使我们能够在广泛的密度和条件下研究他们，最大限度地提高我们发现我们所寻求的关系的机会。我们将使用各种各样的措施的免疫概况，更新和更传统的，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体的免疫特征与我们已知的特定感染（也是从过去的经验中）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.