Geography, networks, and risk in disease transmission

描述(由申请人提供)： 当前的网络理论认为，本地(个人)选择会产生全球网络结构和风险配置。我们基于这样的概念框架，即在市中心环境中，这些地方选择导致来自多个来源的多个暴露渠道(复合风险)；促进传播的网络结构；以及促进与同一网络中的那些人联系的地理接近。正是这三个因素的相互作用，使艾滋病毒和性传播感染在这种环境中保持了地方性。我们的具体目标是(1)描述在艾滋病毒高负担和低负担地区因吸毒和性行为而面临风险的人的行为、网络和地理特征。(2)评估这些行为、网络和地理因素对艾滋病毒高负担和低负担地区七种性传播和血液传播感染(艾滋病毒、丙型肝炎病毒、单纯疱疹病毒-2、梅毒、淋病、衣原体感染和滴虫病)的患病率和发病率的综合影响及其动态。我们的假设包括社会距离(由测地线衡量，或相连群体中两个人之间的最短距离)与地理距离(由这两个人之间的度量距离衡量)之间存在强烈关联的预期；证明复合风险的存在和重要性；确认小型网络具有促进传播的结构特征；以及定量证实这些特征在高负担艾滋病毒地区比低负担艾滋病毒地区更重要。我们将使用人种学方法在5个高负担邮政编码和5个低负担邮政编码中分别确定3个“种子”，并将使用链式设计建立30个网络，每个网络约25人，他们将在基线和相隔9个月的3次后续接触中接受面谈和测试。他们的第一级联系人将被寻找、面试和测试，以在每一波面试中产生750人的样本。我们将使用流行病学、网络和地理空间分析方法来检验我们的基本假设。如果这些假设得到证实，研究结果将表明，在地方性疾病环境中减少风险的分类方法不太可能成功；地理关系是理解疾病传播的基本重要因素；地理上的接近支持有重点、有针对性的干预的必要性；以及将网络结构和动态与疾病传播联系起来的未来建模工作将得到加强。

DESCRIPTION (provided by applicant): A current network theory proposes that local (personal) choices generate global network structure and risk configuration. We base this proposal on the conceptual framework that, in inner city environments, these local choices result in multiple channels of exposure from multiple sources (compound risk); a network structure that facilitates transmission; and geographic proximity that promotes contact with those in the same network. It is the interaction of these three factors that maintains endemicity of HIV and STIs in such settings. Our specific aims are (1) To delineate the behavioral, network, and geographic characteristics of persons who are at risk because of their drug-using and sexual activity in high- and low-burden HIV areas.; (2) To assess the combined influence of these behavioral, network, and geographic factors and their dynamics on the prevalence and incidence of seven sexually transmitted and blood-borne infections (HIV, HCV, HSV-2, Syphilis, Gonorrhea, Chlamydial infection, and Trichomoniasis) in the areas with high and low burden of HIV. Our hypotheses include an expectation of a strong association between social distance (as measured by the geodesic, or shortest distance between two persons in a connected group) and geographic distance (as measured by the metric distance between those two persons); demonstration of the presence and importance of compound risk; confirmation that small networks have structural features that facilitate transmission, and quantitative confirmation of the greater importance of these characteristics in high-burden HIV areas compared to low-burden HIV areas. We will use ethnographic methods to identify 3 "seeds" in each of 5 high-burden and 5 low-burden zip codes, and will use a chain-link design to construct 30 networks of approximately 25 persons each who will be interviewed and tested at baseline and in three follow-up contacts 9 months apart. Their first-degree contacts will be sought, interviewed and tested, to produce a sample of 750 persons at each interview wave. We will use epidemiologic, network, and geospatial analytic methods to examine our underlying hypotheses. If the hypotheses are substantiated, the findings will suggest that categorical approaches to risk reduction in the endemic disease environment are unlikely to be successful; that geographic relationships are factors of basic importance in understanding disease transmission; that geographic proximity supports the need for focused, targeted intervention; and that future modeling efforts relating network structure and dynamics to disease transmission will be enhanced.