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

病原体适应性是由其人类和动物宿主如何相互作用以及环境如何产生易感性和传播模式来驱动的。该项目旨在利用不同地理环境中的宿主、病原体和环境数据，了解病原体适应性的驱动因素以及人类干预措施如何影响这一点。计算模拟将使用宿主人口统计学和病原体传播模型来构建，这些模型跟踪作为宿主接触模式，人口统计学和易感性概况以及其他生态和环境驱动因素的函数的适应性。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，两种疫苗（RotaTeq和Rotarix）的开发导致几个国家引入轮状病毒疫苗接种。总的来说，实施疫苗的国家的轮状病毒胃肠炎病例大幅减少，世界范围内的一些经济评价证明了疫苗实施的功效和有效性。然而，这些主要限于低死亡率的高收入国家，2013年，全球5岁以下儿童因轮状病毒死亡的人数估计约为215，000人。此外，个体之间的传播以及天然和疫苗诱导的免疫力的发展所涉及的确切机制尚未完全理解。这种不确定性导致了许多不同的轮状病毒传播的建模方法。随着疫苗接种前和接种后数据的增加，特别是在高收入环境中，本项目旨在更详细地调查这些潜在机制和适当的建模方法。近年来，不同人口和气候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，它们正处于或一直处于人口结构转型的不同阶段，这涉及出生率和死亡率从高转向低。近几十年来，一些国家一直在迅速转型，改变了其人口的基本结构。宿主的人口统计学在决定病原体的存活和繁殖率方面起着重要作用，由于人口增长、老龄化和迁移而引起的人口变化可能对这些产生巨大影响。然而，模型往往通过粗略的假设简化了潜在的人口统计过程，因为它们对病原体的影响和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和疫苗保护模型的更好理解，该项目将探讨人口变化可能对轮状病毒传播的影响，以及不同地理环境中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.