Changes to pathogen fitness as a result of population growth, ageing and migration

病原体的适应性是由其人类和动物宿主相互作用的方式以及环境来创造易感性和传播模式所驱动的。该项目旨在使用不同地理环境中的宿主、病原体和环境数据来了解病原体适应性的驱动因素以及人类干预可能如何影响这一点。将使用宿主人口学和病原体传播模型构建计算模拟，这些模型跟踪作为宿主接触模式、人口统计学和易感性特征以及其他生态和环境驱动因素的健康状况。轮状病毒是全球5岁以下儿童严重腹泻的最常见原因。2006年开发的两种疫苗(RotaTeq和Rotarix)导致几个国家采用轮状病毒疫苗接种。总体而言，在实施疫苗的国家中轮状病毒胃肠炎病例的急剧下降和世界各地的一些经济评估证明了疫苗实施的效力和效力。然而，这主要限于低死亡率、高收入国家，2013年，全球5岁以下儿童死于轮状病毒的人数估计约为215,000人。此外，涉及个体间传播以及自然和疫苗诱导免疫发展的确切机制尚不完全清楚。这种不确定性导致了轮状病毒传播的一些不同的建模方法。随着越来越多的疫苗接种前和接种后数据可用，特别是在高收入环境中，该项目旨在更详细地调查这些基本机制和适当的建模方法。近年来，不同人口和温带环境的国家已经或正在开始实施疫苗接种计划。这些国家包括一些低收入国家，它们正处于和一直在经历人口结构转型的不同阶段，这涉及出生率和死亡率从高到低的转变。近几十年来，一些国家迅速转型，改变了其人口的基本结构。寄主人口统计学在决定病原菌的存活率和繁殖率方面起着重要作用，人口增长、老龄化和迁徙引起的人口统计学差异可能会对此产生重大影响。然而，模型往往通过作出粗略的假设来简化潜在的人口统计过程，因为它们对病原体的影响和与病原体的相互作用并没有得到很好的理解或经常被忽视。随着对轮状病毒传播模型和疫苗保护的更好理解，该项目将探索人口结构变化可能对轮状病毒传播产生的影响，以及在不同地理环境下的短期和长期干预措施的预期影响。

Pathogen fitness is driven by how its human and animal hosts interact with each other and the environment to create patterns of susceptibility and transmission. This project aims to use host, pathogen and environmental data in different geographical settings to understand the drivers of pathogen fitness and how human interventions may affect this. Computational simulations will be constructed using host demography and pathogen transmission models that track fitness as a function of host contact patterns, demographic and susceptibility profiles, and other ecological and environmental drivers.Rotavirus is globally the most common cause of severe diarrhoea amongst children under the age of 5 years. The development of two vaccines (RotaTeq and Rotarix) in 2006 led to several countries introducing rotavirus vaccination. In general, drastic decreases in rotavirus gastroenteritis cases in countries that implemented the vaccine and a number of economic evaluations worldwide have demonstrated the efficacy and effectiveness of vaccine implementation. Nevertheless, these have mostly been limited to low-mortality high income countries and for 2013 the number of deaths in children under 5 years of age due to rotavirus was estimated to be around 215,000 globally. Moreover, the exact mechanisms involved in the transmission between individuals and in the development of both natural and vaccine induced immunity are yet to be fully understood. This uncertainty has resulted in a number of different modelling approaches for rotavirus transmission. With an increasing amount of pre- and post-vaccination data available, especially in higher income settings, this project aims to investigate these underlying mechanisms and appropriate modelling approaches in more detail. In recent years, countries in different demographic and temperate settings have been or are beginning to implement vaccination programs. These include a number of lower income countries that are at and have been undergoing different stages of the demographic transition, which involves a shift from high to lower birth and death rates. Some countries have been transitioning rapidly in recent decades, changing the fundamental structures of their populations. Host demographics play an important role in determining the survival and reproduction rate of a pathogen and demographic variation due to population growth, ageing and migration may have drastic effects on these. However, models often simplify the underlying demographic processes by making crude assumptions, as their effects on and interactions with pathogens are not very well understood or frequently overlooked. With a better understanding of modelling rotavirus transmission and vaccine protection, this project will explore the effects demographic variation may have on rotavirus transmission and the prospective impact of interventions in the short and long term in different geographical settings.