Epidemiology, Ecology and Socio-Economics of Disease Emergence in Nairobi

城市化的全球趋势日益增强。已经，半个世界？中国的人口生活在城市地区，而且这一比例还在上升。人们普遍认为，城市化，特别是与贫穷和恶劣生活条件相联系的城市化，会增加疾病的风险。此外，一些有影响力的报告假设，城市化的增加会增加新病原体出现的风险。尽管这个想法听起来很合理，但几乎没有确凿的证据支持它：城市化真的会造成新疾病的风险吗？如果是这样，又是如何造成的？没有这些信息，决策者很难采取任何实际行动来减轻城市化带来的任何风险。我们提出了一项研究，涉及专家在广泛的相关主题，调查这个问题的具体背景下，城市畜牧业在肯尼亚内罗毕。我们将询问家畜饲养和儿童腹泻病之间是否存在关联，但也要解决家畜的存在如何影响城市微生物生态的更广泛问题：人类，家畜，其他动物（如啮齿动物和鸟类）的微生物菌群以及更广泛的环境是如何相关的？我们将通过收集一种普遍存在的细菌的分离物来做到这一点？大肠杆菌？从所有这些环境中分离出来，并进行基因分析，以显示细菌是如何相关的。这将使我们能够确定？微生物足迹以及这种足迹是否延伸到人类。我们认为，新的病原体最有可能通过人类接触已知微生物的相同途径出现。围绕着这个概念，？价值链？（将供应链置于其社会经济背景下）-将研究城市畜牧业的驱动因素，将这些因素与其他畜牧产品来源联系起来，并探讨各种做法如何与供求关系联系起来。这将告诉我们，随着城市畜牧业越来越普遍，粮食安全越来越具有挑战性，不仅在内罗毕，而且在全世界，这些风险可能会如何变化。最后，我们将结果与政策的制定：立法关于畜牧业在内罗毕正在发生变化，这项研究将提供新的法规的潜在有效性的支持证据，平衡公共卫生风险与粮食安全和收入的需要。

There is a global trend towards increasing urbanization. Already, half the world?s population lives in urban areas, and that proportion is rising. It is widely accepted that urbanization, especially when associated with poverty and poor living conditions, increases the risk of disease. Moreover, a number of influential reports have postulated that increased urbanization increases the risk of the emergence of novel pathogens. Though this idea sounds reasonable there is very little hard evidence to back it up: does urbanization really pose a risk of emerging disease and, if so, how? Without this information it is very difficult for policy makers to do anything practical to mitigate any risks that urbanization poses. We propose a study involving experts in a wide range of relevant subjects to investigate this issue in the specific context of urban livestock keeping in Nairobi, Kenya. We will ask whether there is an association between livestock keeping and diarrhoeal disease in children, but also tackle the broader question of how the presence of livestock affects the microbial ecology of the city: how are the microbial floras of humans, livestock, other animals (such as rodents and birds) and the wider environment related? We will do this by collecting isolates of a ubiquitous bacterium ? Escherichia coli ? from all these environments and undertaking genetic analysis to show how the bacteria are related. This will allow us to determine the ?microbial footprint? of urban livestock and whether this footprint extends to the human population. We propose that novel pathogens are most likely to emerge via the same routes by which humans become exposed to known microbes.At the same time, we will undertake a series of social and economic studies ? centred on the concept of the ?value chain? (which places supply chains in their socio-economic context) - which will examine the drivers of urban livestock keeping, relate these to other sources of livestock products, and explore how practices are related to supply and demand. This will tell us how the risks are likely to change in the future as urban livestock keeping becomes more widespread and food security more challenging, not just in Nairobi but worldwide. Finally, we will relate the results to policy development: legislation regarding livestock keeping in Nairobi is changing and this study will provide supporting evidence for the potential effectiveness of new regulations, balancing public health risks with the need for food security and income.