The Spatiotemporal Anatomy of Seasonal Influenza in the United States, 1968

描述（由申请人提供）：季节性对自然系统及其种群的时空动态具有重要影响，是温带地区流感传播背后的驱动力。虽然温带国家流感的季节性已得到广泛认识，但美国流感的区域间传播尚未得到很好的描述。本研究将通过使用每周肺炎和流感（P&I）死亡率来模拟1968年至2007年间美国季节性流感的区域间和城市间流动，研究整个美国流感的季节性。该项目旨在确定美国季节性流感传播的潜在浪潮，以及流感时间和传播对特定流感季节主要流行流感类型或亚型的依赖关系。这一目标将通过实现以下目标来实现：1)确定1968年至2007年美国季节性流感的时空格局；2)比较美国季节性流感的主要类型和亚型的时空格局；3)确定美国流感传播的源头地点；4)确定季节性流感在美国的主要传播过程，将使用从P&I到死亡的平均时间来确定每个流感季节的流行时间和波浪进展方向。它还将用于确定流感传播的种子位置，并评估传播速度。将使用普通最小二乘来开发每个流感季节的线性趋势面，并描绘每个流感季节空间进展的主要趋势。空间自相关将用于检测美国季节性流感的主要传播过程（如传染性，分层或混合过程）。此外，还将确定季节性流感在美国传播的平均时间，以及按主要流感亚型和季节划分的地区高峰和全国高峰之间的平均时间。识别时空格局有助于提高疫情预测和预防水平。本研究将确定美国季节性流感的时空特征，并显示这些特征是否因主要流感亚型而异。完成这项研究将极大地帮助公共卫生专业人员改进流感干预战略，包括更好地安置和分发疫苗和其他药物。

DESCRIPTION (provided by applicant): Seasonality has a major effect on the spatiotemporal dynamics of natural systems and their populations and is the driving force behind the transmission of influenza in temperate regions. Although the seasonality of influenza in temperate countries is widely recognized, inter-regional spread of influenza in the United States have not been well characterized. This research will study the seasonality of influenza throughout the United States by using weekly pneumonia and influenza (P&I) mortality to model inter-region and inter-city movement of seasonal influenza in the United States between 1968 and 2007. This project aims to identify the underlying wave of seasonal influenza spread in the United States and the dependence of the timing and spread of influenza on the dominant circulating influenza type or subtype in a given influenza season. This goal will be achieved by accomplishing the following aims: 1) identifying the spatial and temporal patterns of seasonal influenza in the U.S. from 1968 to 2007, 2) comparing the spatial and temporal patterns of seasonal influenza in the U.S. by dominant type or subtype of influenza, 3) identifying source locations of influenza transmission in the U.S., 4) and determining the dominant spreading process of seasonal influenza in the U.S. Average time to death from P&I will be used to determine the epidemic timing and direction of wave progression for each influenza season. It will also be used to identify seed locations for influenza transmission and assess the velocity of wave progression. Ordinary least squares will be used in order to develop linear trend surfaces for each influenza season and to depict the main trend in the spatial progression of each influenza season. Spatial autocorrelation will be used to detect the dominant spreading process of seasonal influenza in the U.S. (e.g. contagious, hierarchical, or mixed process). In addition, the average time seasonal influenza takes to spread across the United States and the average time between regional peak and national peak by dominant influenza subtype and season will be determined. Identifying spatiotemporal patterns could improve epidemic prediction and prevention. This research will determine the spatial and temporal characteristics of seasonal influenza in the U.S. and show if these characteristics differ by dominant influenza sub-type. Accomplishing this research will greatly aid public health professionals in refining influenza intervention strategies that include better placement and distribution of vaccines and other medicines. PUBLIC HEALTH RELEVANCE: The completion of the proposed research has broad application for the planning of intervention strategies for pandemic and epidemic influenza in the U.S. Knowledge of the timing and spatial spread of influenza could severely limit the morbidity and mortality associated with epidemic influenza, as well as with a future pandemic. The knowledge gained as a result of this dissertation will allow public health officials to refine currnt influenza intervention strategies in order to more effectively and efficiently utilize influenza interventions.