Mechanistic models of host movement to understand disease dynamics in variable environments

在加拿大，过去20年来出现了新的野生动物疾病，现有疾病的模式发生了重大变化。这些变化强调了研究疾病动力学的必要性。当易感宿主接触传染性宿主或寄生虫时，疾病传播。这些遭遇率在很大程度上取决于宿主的移动方式，然而，大多数疾病传播的数学模型都没有明确考虑宿主的移动。此外，温度、湿度和其他非生物因素影响寄生虫的感染性和寄生虫生命阶段的成熟速度。季节性的强度和机制都会影响疾病的动态。寄生虫影响宿主的移动方式，这会影响寄生虫的传播和寄生虫毒力等特征的演变。我的研究小组将调查宿主的移动如何影响所导致的流行病的类型。我们将考虑不同类型的运动模型，包括相关和有偏随机游动和状态空间模型。我们将研究波动的环境条件对自由生活的寄生虫传播的影响。我们还将通过推导和分析数学模型来研究寄生虫毒力的演变，其中宿主运动和/或寄生虫感染性，寄生虫脱落率和疾病引起的死亡率之间存在权衡。在所有情况下，将使用数学和计算技术分析模型。 这项研究将利用最近在开发动物运动的机械模型方面取得的进展，并将为传染病传播的研究提供新的概念，定量和计算工具。我们将得到的模型改进了现有理论的生物现实主义，并可能导致更好地理解疾病动力学。对于一个具体的案例研究，我们将应用我们开发的理论来了解脑蠕虫在纽芬兰驯鹿群中的传播。该研究计划将支持1名博士生，4名硕士生和4名本科生研究人员的培训。这些学生将接受数学建模和理论生物学方面的培训，并将获得跨学科研究的宝贵经验。

In Canada, over the last two decades new wildlife diseases have emerged and patterns of existing diseases have changed substantially. These changes highlight the need for research that investigates disease dynamics. Diseases are spread when a susceptible host contacts an infectious host or a parasite. These rates of encounter depend strongly on how hosts move, and yet, most mathematical models of disease spread do not explicitly consider host movement. In addition, temperature, humidity and other abiotic factors affect both the infectivity of parasites and the rate of maturation through parasite life stages. Both the strength and mechanisms of seasonality will affect disease dynamics. Parasites affect how hosts move and this affects parasite spread and the evolution of characteristics such as parasite virulence. My research group will investigate how host movement affects the types of epidemics that result. We will consider different types of movement models including correlated and biased random walks and state-space models. We will investigate the effect of fluctuating environmental conditions on the spread of free-living parasites. We will also investigate the evolution of parasite virulence by deriving and analyzing mathematical models where a trade-off exists between the rate of host movement and/or parasite infectivity, the parasite shedding rate, and the disease-induced death rate. In all cases, the models will be analyzed using mathematical and computational techniques. This research will capitalize on recent progress in developing mechanistic models of animal movement and will contribute new conceptual, quantitative, and computational tools to the study of infectious disease spread. The models that we will derive improve the biological realism of existing theory and are likely to lead to a better understanding of disease dynamics. For a specific case study, we will apply the theory we develop to understand the spread of brain worm in declining herds of caribou in Newfoundland. This research program will support the training of 1 PhD student, 4 MSc students and 4 undergraduate researchers. These students will be trained in mathematical modelling and theoretical biology and will gain valuable experience in interdisciplinary research.