Improving projections for the future of bluetongue and its vectors under scenarios of climate and environmental change

气候变化将如何影响威胁我们健康和粮食安全的疾病？我们有充分的理由相信，气候变化将导致许多传染病传播到新的地方或更频繁地发生，特别是病媒传播的疾病——那些由节肢动物（主要是昆虫）害虫传播的疾病，如疟疾和登革热。这是因为传播这些疾病的节肢动物本身受到气候和它们所处环境的影响。虽然我们认识到气候变化将影响病媒传播的疾病，但我们目前预测未来实际会发生什么情况的能力非常有限——甚至不能说下一个威胁我们的是哪种疾病。因此，我们无法向决策者提供他们采取必要和及时措施所需的信息。我们在这里的主要目的是开发一种工具，用于探索未来气候和环境条件下病媒疾病暴发的性质，并评估可能需要哪些干预措施来控制它们。我们开发了蓝舌病（BT）的工具，这是一种由微小的叮咬昆虫（蠓）传播的羊和牛的病毒性疾病。经过几十年的间隔，BT于1998年在欧洲重新出现，并在接下来的十年中蔓延到欧洲大陆的大部分地区，包括2007年的英国，导致数百万动物死亡，其中大部分是羊。这次BT疫情是前所未有的：是有史以来持续时间最长、规模最大的一次；包括意大利、法国、德国和英国在内的许多国家首次受到影响；疾病发生在比以往更远的北方；大量的病毒株参与其中。此外，这种疾病继续构成威胁：我们的农场里有大量的蠓，它们以我们的动物为食，而且对于大多数病毒株，没有立即可用的疫苗。我们之所以选择BT，是因为它被认为是应对气候变化而出现的一种疾病的典型例子。我们建议开发的工具是一个新的BT在英国农场之间传播的数学模型，与未来最先进的气候模型预测相结合，这样我们就可以研究这种疾病在未来气候条件下（到2050年）的传播方式，以及在爆发时可能需要采取哪些干预措施。然而，到2050年，不仅仅是气候会发生变化。其他环境变化也可能影响英国电信，尽管我们对这些“驱动因素”的理解有限，对它们将如何变化的了解也很少。我们将举办一次研讨会，征求专家对非气候驱动因素及其未来可能变化的情景的意见；然后，我们将在我们的建模系统中考虑这些变化的影响。基于模型的对未来的预测总是不确定的。尝试测量这种不确定性的规模，以及它在模型中产生的位置是有用的，以便更好地理解预测的局限性，并指导进一步的工作。我们将调查我们模型中不确定性的主要来源是由于我们对BT不够了解，还是因为我们对BT将发生的未来条件不够清楚。最后，我们已经知道，由于对传播BT的昆虫的生物学知识有限，我们的疾病模型中出现了一些不确定性。我们将在英格兰和威尔士的144个农场捕获库蠓，以便绘制它们的地图，用天气和气候数据对结果进行统计分析，以改进我们的模型；并在少数农场进行详细的研究，以调查蠓传播BT病毒的能力。

How will climate change affect the diseases that threaten our health and food security? We have good reason to believe that climate change will cause a number of infectious diseases to spread to new places or occur more often, particularly vector-borne diseases - those spread by arthropod (mostly insect) pests, such as malaria and dengue. This is because the arthropods that spread these diseases are themselves affected by climate and the environment they live in. While we recognise that climate change will affect vector-borne diseases, we currently have very limited ability to make predictions about what will actually happen in future - even to say which disease will threaten next. We cannot, therefore, give policy makers the information they need to be able to take necessary and timely measures.Our main aim here is to develop a tool for exploring the nature of vector-disease outbreaks under future conditions of climate and environment, and to assess what interventions may be needed to contain them. We develop the tool for bluetongue (BT), a viral disease of sheep and cattle that is spread by tiny biting insects (midges). BT reappeared in Europe in 1998 after a gap of several decades and, in the next ten years, spread over most of the continent, including the UK in 2007, leading to the deaths of millions of animals, mostly sheep. This BT outbreak was unprecedented: the longest and largest on record; numerous countries, including Italy, France, Germany and UK, were affected for the first time; disease occurred much further north than ever before; and a large number of viral strains were involved. Furthermore, the disease continues to threaten: midges are hugely abundant on our farms, feeding on our animals, and for the majority of viral strains there is no vaccine immediately available for use.We have chosen BT because it is considered a prime example of a disease that has emerged already in response to climate change. The tool we propose to develop is a novel mathematical model for the spread of BT between farms in GB, integrated with state-of-the-art climate model projections of the future, so that we can investigate the way in which the disease will spread under conditions of future climate (up to 2050), and what interventions may be required in the event of an outbreak. It will not only be climate that changes by 2050 however. Other environmental changes may also affect BT, although we have only limited understanding of what these 'drivers' are and very little knowledge of how they will change. We will hold a workshop to solicit expert opinion about non-climate drivers and scenarios for how they might change in future; and we will then consider the effect of these changes within our modelling system.Model-based predictions of the future are always uncertain. It is useful to try to measure the scale of this uncertainty, and also from where in the model it is arising, so as to better understand the limitations of the predictions and to guide further work. We will investigate whether the main source of uncertainty in our model arises because we do not understand BT well enough, or because we have insufficient clarity about the future conditions that BT will occur in.Finally, we know already that some uncertainty arises in our disease model from limited knowledge of the biology of the insects that spread BT. We will trap Culicoides at 144 farms across England and Wales in order to map them, statistically analyse the results with weather and climate data to improve our models; and undertake detailed studies on a smaller number of farms to investigate how able the midges are to spread BT virus.