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

全球的趋势是日益城市化。已经，半个世界？美国人口居住在城市地区，而且这一比例正在上升。人们普遍认为，城市化，特别是与贫穷和恶劣的生活条件相关联的城市化，增加了患病的风险。此外，一些有影响力的报告假设，城市化的增加增加了出现新型病原体的风险。虽然这个想法听起来很合理，但几乎没有确凿的证据来支持它：城市化真的会带来新疾病的风险吗？如果是的话，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风险。我们建议开展一项涉及广泛相关学科专家的研究，在肯尼亚内罗毕城市牲畜饲养的具体背景下调查这一问题。我们将探讨牲畜饲养与儿童腹泻病之间是否存在关联，但也将探讨更广泛的问题，即牲畜的存在如何影响城市的微生物生态：人类、牲畜、其他动物（如啮齿动物和鸟类）的微生物群落与更广泛的环境之间是如何关联的？我们将通过收集一种无处不在的细菌的分离物来做到这一点？大肠杆菌？从所有这些环境中进行基因分析，以显示细菌之间的关系。这能让我们确定？微生物的足迹吗?以及这种足迹是否会延伸到人类身上。我们认为，新的病原体最有可能通过人类暴露于已知微生物的相同途径出现。与此同时，我们将进行一系列社会和经济研究。以？价值链?（将供应链置于其社会经济背景下）-它将审查城市牲畜饲养的驱动因素，将这些因素与其他畜产品来源联系起来，并探索实践与供需之间的关系。这将告诉我们，随着城市牲畜饲养变得更加普遍，粮食安全面临更大挑战（不仅在内罗毕，而且在全世界），未来的风险可能会发生怎样的变化。最后，我们将把研究结果与政策制定联系起来：内罗毕有关牲畜饲养的立法正在发生变化，这项研究将为新法规的潜在效力提供支持性证据，在公共卫生风险与粮食安全和收入需求之间取得平衡。

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.