Geography, networks, and risk in disease transmission

描述（由申请人提供）： 当前的网络理论认为，局部（个人）选择产生全球网络结构和风险配置。我们的基础上的概念框架，在内城环境中，这些地方的选择导致多个渠道的暴露从多个来源（复合风险）;网络结构，促进传输;和地理上的接近，促进接触那些在同一个网络。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些环境中保持地方性。我们的具体目标是：（1）描述艾滋病高负担和低负担地区因吸毒和性活动而处于危险中的人的行为、网络和地理特征; (2)评估这些行为、网络和地理因素及其动态对HIV高负担和低负担地区7种性传播和血液传播感染（HIV、HCV、HSV-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。我们的假设包括社会距离与社会行为之间的强烈关联（由测地线测量，或连接组中两个人之间的最短距离）和地理距离（以这两个人之间的度量距离衡量）;证明复合风险的存在和重要性;确认小型网络具有便于传输的结构特征，并从数量上证实了这些特征在艾滋病毒高负担地区比在艾滋病毒低负担地区更为重要。我们将使用人种学方法在5个高负担和5个低负担的邮政编码中确定3个“种子”，并将使用链式设计构建30个网络，每个网络约25人，他们将在基线和间隔9个月的三次随访接触中接受采访和测试。我们会寻找他们的第一级接触者，进行面试和测试，以便在每一轮面试中产生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查我们的基本假设。如果这些假设得到证实，研究结果将表明，在地方病环境中降低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;地理邻近性支持需要有针对性的干预措施;未来将加强与疾病传播相关的网络结构和动态建模工作。

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.