GOING UNDERGROUND: HUMAN PATHOGENS IN THE SOIL-WATER ENVIRONMENT

人类病原体如大肠杆菌O157（大肠杆菌）的暴发由于对健康和生命的潜在严重威胁而引起媒体的关注。受污染的食物并不是感染的唯一来源。微生物病原体在农村和城市环境中都很普遍，我们周围的土壤和水资源可能是这些生物体移动的储存或途径。目前，对这一问题的最好理解是在农村环境中，农场动物通过其粪便向环境提供病原体来源。以前的工作展示了病原体如何在土壤中生存和移动，并提供了它们在源头和在河流、水库和浅井等脆弱的“受体”中丰度的信息。最近的“集水区规模”模型能够将农业用地的变化（影响病原体的输入、生存和移动）与下游地区的病原体水平联系起来，例如沿海洗浴水域和贝类养殖场。气候、城市发展、水资源政策的趋势以及人类对健康和环境危害的态度可能会增加土壤和水资源中人类病原体的潜在风险。洪水的增加、地下水的抽取、利用运河和河网在全国范围内分配水，以及重新使用未经处理的“灰”水，都可能影响我们在城镇和农村地区使用的水和土壤的病原体负荷。其他潜在的来源包括下水道泄漏、垃圾倾倒，甚至是工业或“生物恐怖主义”中意外或故意释放的病原体。为了评估和管理这种普遍的环境风险，我们需要确定和解决目前尚未解决的许多科学、流行病学和政策问题。其中包括：什么样的土壤微环境可能延长病原体的生存时间？土壤含水量的变化如何影响病原体在土壤中的运动和储存？在空气或表面污染消散后，土壤是否会储存和运输有害微生物？我们能否测量目前环境病原体污染对普通人群健康的影响？危害是急性的（由于单一事件）还是慢性的（由于背景污染）？气候变化、土地利用变化和极端事件将如何影响病原体源和受体的空间分布？城市人口是否因为缺乏接触而比农村人口更容易感染病原体？哪些活动或社会因素可能会增加一个人的脆弱程度？应如何规划和制定健康保护措施，以预防未来土壤-水环境中病原体的健康风险？为了应对这些挑战，我们需要广泛的技能基础，包括微生物学和病原体与土壤和水相互作用的物理过程；集水区风险评估；水资源管理；人类健康和流行病学；以及环境/公共卫生政策。该提案将在15个月的时间内召开5次主题会议，涉及一个核心跨学科工作组和额外邀请的专门知识。结果将是：对英国的科学现状、风险和政策进行全面的批判性审查，发表在高质量的同行评审期刊上；一套关于研究重点和政策方向的详细建议；并至少提出一项基于评审结果的更大规模跨学科研究联盟的建议。

Outbreaks of human pathogens such as Escherichia coli O157 (E. coli) attract media attention due to the potentially severe threat to health and life. Contaminated food is not the only source of infection. Microbial pathogens are widespread in both rural and urban environments and the soils and water resources around us may act as stores or pathways for movement of these organisms. At present, the problem is best understood in a rural context where farm animals provide a source of pathogens to the environment via their wastes. Previous work shows how pathogens survive and move through soils and provides information on their abundance at source and in vulnerable 'receptors' such as rivers, reservoirs and shallow wells. More recent 'catchment scale' models are able to relate variations in agricultural land use (which affects pathogen input, survival and movement) to pathogen levels in areas downstream, such as coastal bathing waters and shellfish beds. Trends in climate, urban development, water resource policy and human attitudes towards health and environmental hazards may increase the potential risk from human pathogens in soil and water resources. An increase in flooding, abstraction of groundwater, use of the canal and river network to distribute water around the country, and reuse of lightly treated 'grey' water may affect the pathogen load of the water and soils we use in towns and cities as well as rural areas. Other potential sources are leaking sewers, fly-tipping and even accidental or deliberate release of pathogens from industry or 'bio-terrorism'. In order to assess and manage this general environmental risk we need to identify and address many scientific, epidemiological and policy questions which are currently unanswered. These include: What soil microenvironments might prolong pathogen survival? How does changing soil water content affect pathogen movement and storage in soils? Will soils store and transport hazardous microbes after air or surface contamination has dispersed? Can we measure the current health effects of environmental pathogen contamination in the general population? Is the hazard acute (due to single events) or chronic (due to background contamination)? How will climate change, shifts in land use and extreme events affect the spatial distribution of pathogen sources and receptors? Are urban populations more vulnerable to pathogens than rural populations through lack of exposure? What activities or social factors might increase a person's level of vulnerability? How should planning and health protection measures be constructed to pre-empt future health risks from pathogens in the soil-water environment? To respond to these challenges we require a broad skills base covering microbiology and the physical processes of pathogen interactions with soil and water; catchment risk assessment; water resource management; human health and epidemiology; and environmental / public health policy. This proposal will convene 5 themed meetings over a 15 month period involving a core interdisciplinary Working Group and additional invited expertise. The outcomes will be: a comprehensive critical review of the current state of the science, risks and policy in the UK, published in a high quality peer-reviewed journal; a detailed set of recommendations for research priorities and policy directions; and at least one proposal for a larger-scale interdisciplinary research consortium based on the outcomes of the review.