Spatio-temporally explicit estimation of R0 for pathogens with environmentally-mediated transmission

 描述（由申请人提供）：间接病原体传播可以是媒介或环境介导的。后者是野生动物和牲畜中一些重要的多宿主疾病，包括几种人畜共患病（传染给人类的疾病）的主要感染方式，并与病原体在环境宿主中存在的地区的宿主移动和觅食明确相关。在这样的系统中计算R 0需要我们估计每个水库对新情况的贡献。要做到这一点，我们必须将传播过程分解为病原体脱落、环境持久性和宿主接触（病原体摄入或吸入）三个部分。这种接触率的特点可以从本地主机移动和觅食模式的组合驱动的大规模的季节性资源选择。持久的环境病原体水库可以模拟为个人，当地的感染区与自己的人口和空间分布，这些区域的生活史影响主机觅食本地。在这个为期4年的EEID项目中，我们提供了一种新的地理空间和数学相结合的方法来估计R 0的环境介导的传输。然后，我们将评估影响传输过程不同组成部分的控制策略的有效性。为此，我们提出了以下具体目标：具体目标1：通过量化宿主移动和觅食行为，表征局部感染区的空间分布和人口统计学，表征控制宿主觅食和病原体持久性的环境因素，推导出描述与局部感染区的宿主特异性接触率的函数;具体目标2：应用这些函数估算炭疽的R 0（炭疽杆菌的间接传播）使用来自在自由放养的食草动物中具有活性炭疽的两个区域的经验数据集-有和没有疾病控制的对比系统;具体目标3：评估我们的新R 0估计与野生动物和牲畜系统疾病控制策略相关的概念和实际影响，包括人类疾病仍然是主要威胁的那些系统。

 DESCRIPTION (provided by applicant): Indirect pathogen transmission can be vectored or environmentally-mediated. The latter is the primary mode of infection for a number of important multi-host diseases in wildlife and livestock, including several zoonoses (diseases that spillover into humans) and is explicitly linked to host movements and foraging in areas where the pathogen is maintained in environmental reservoirs. Calculating R0 in such systems requires that we estimate the contribution of each reservoir to new cases. To do this we must unpack the transmission process into its pathogen shedding, environmental persistence, and host contact (pathogen ingestion or inhalation) components. Such contact rates can be characterized from a combination of local host movement and foraging patterns driven by larger-scale seasonal resource selection. Persistent environmental pathogen reservoirs can be modeled as individual, local infectious zones with their own demography and spatial distribution; life history of these zones influence host foraging locally. In this 4-year EEID project, we provide a novel combined geospatial and mathematical approach for estimating R0 for environmentally-mediated transmission. We will then assess efficacies of control strategies impacting different components of the transmission process. Toward this, we propose the following specific aims: Specific Aim 1: Derive functions to describe host-specific contact rates with local infectious zones by quantifying host movement and foraging behavior, characterizing the spatial distribution and demography of local infectious zones, characterizing the environmental factors controlling host foraging and pathogen persistence; Specific Aim 2: Apply these functions to estimating R0 for anthrax (indirect transmission of Bacillus anthracis) using empirical datasets from two regions with active anthrax in free ranging herbivores-contrasting systems with and without disease control; Specific Aim 3: Evaluate the conceptual and practical impact of our novel R0 estimates as related to disease control strategies for wildlife and livestock systems, including those where human disease remains a major threat.