Dynamics and Evolution of Emerging Diseases with Applications to Amphibians

新发疾病的动态和演变及其在两栖动物中的应用

• 批准号: 0201105
• 负责人: Linda Allen
• 金额: $ 91.5万
• 依托单位: Texas Tech University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0201105&HistoricalAwards=false
• 关键词: Dynamics; Evolution; Emerging; Diseases; Applications

The goals of this project are threefold: (1) to contribute to the mathematical theory of the evolution of host-pathogen systems, (2) to apply the theory to amphibian populations, and (3) to conduct an intensive biological investigation of amphibian populations and their associated diseases on the Southern High Plains. Deterministic and stochastic structured epidemic models with host and pathogen genetics will be developed, analyzed, and numerically simulated. Discrete and continuous time structured models are based on difference equations, differential equations, Markov chains, and stochastic differential equations. The mathematical models will be used to study how disease affects persistence, duration, onset of an epidemic, and population size, and how host and pathogen coevolve in response to various control strategies and to different selection pressures. The models will be applied to specific amphibian populations on the Southern High Plains. The proposed research includes a three-year experimental investigation (two years of intensive fieldwork) to determine amphibian abundance, disease prevalence, and immunological characteristics of two common species of amphibians on the Southern High Plains, the tiger salamander and the plains spadefoot toad. The study sites consist of twelve playa lakes on the Southern High Plains. Mathematical and statistical analyses of the data collected from this study address some basic biological questions about the relationships among amphibian abundance, immune response, disease prevalence, life cycle stage (larvae, juvenile, and adult), landuse practices (grassland versus cropland), and climatic conditions. This study provides important information for determining critical factors that are significant in the transmission and persistence of diseases in amphibians. The emergence of infectious diseases in humans and wildlife is a major threat to public health and to the conservation of global biodiversity. Increased population densities, changes in agricultural and livestock practices, dam building, deforestation, encroachment into wildlife habitat, climate change, environmental pollution, and introduction of pathogens into new areas are some of the factors leading to the emergence of infectious diseases. Understanding the dynamics of the pathogens responsible for the emergence of these diseases and the complex and changing relationship between their host and their environment is needed for potential control of these diseases. A variety of human and environmental influences have caused many host-pathogen systems to evolve and to adapt to these changing influences, making control an even more difficult task. Theoretical studies which contribute to our understanding of the evolution of host-pathogen systems are urgently needed. It is the purpose of this investigation to develop, analyze, and simulate mathematical models based on principles from epidemiology, genetics and population dynamics, to apply these models to host-pathogen systems, and to conduct an experimental investigation on a particular host-pathogen system. The host population models developed in the proposed investigation are applied specifically to amphibian populations. The global decline in amphibian populations is thought to be one of the most pressing and enigmatic environmental problems today. Recent evidence indicates that emerging diseases (viral and fungal pathogens) are responsible for mass die-offs of frogs, toads, and salamanders. Indeed, recent outbreaks of diseases in amphibians should be given serious attention as they may signal environmental change on a global scale that may threaten many organisms. A major part of the proposed research involves a two-year field and three-year laboratory investigation. The purpose of the experimental investigation is to assess amphibian abundance, disease prevalence, and immunological characteristics of two common species of amphibians on the Southern High Plains. This study lays the groundwork for future studies on causes of population declines in amphibians. This grant is made under the Joint DMS/NIGMS Initiative to Support Research Grants in the Area of Mathematical Biology. This is a joint competition sponsored by the Division of Mathematical Sciences (DMS) at the National Science Foundation and the National Institute of General Medical Sciences (NIGMS) at the National Institutes of Health.

该项目的目标是三倍：（1）为宿主 - 病原体系统进化的数学理论做出贡献，（2）将理论应用于两栖群体，以及（3）对两栖动物人群及其相关疾病进行密集的生物学研究。将开发，分析和数值模拟具有宿主和病原体遗传学的确定性和随机结构化流行模型。离散和连续的时间结构化模型基于差异方程，微分方程，马尔可夫链和随机微分方程。数学模型将用于研究疾病如何影响持续性，持续时间，流行病和人口规模的发作，以及宿主和病原体如何响应各种控制策略以及对不同的选择压力。这些模型将应用于南部高平原上的特定两栖动物。拟议的研究包括一项为期三年的实验研究（两年的强化实地调查），以确定两种普通的两栖动物在南部高原，虎sal，虎sal和平原上的两种普通两栖动物的疾病患病率和免疫学特征。研究地点由南部高原上的十二个普拉亚湖组成。从这项研究中收集的数据的数学和统计分析解决了有关两栖动物丰度，免疫反应，疾病患病率，生命周期阶段（幼虫，少年和成人），土地用途实践（草地与农田）和气候状况的一些基本生物学问题。这项研究提供了重要的信息，以确定在两栖动物中疾病的传播和持久性中显着的关键因素。 人类和野生动植物中传染病的出现是对公共卫生和保护全球生物多样性的主要威胁。人口密度增加，农业和牲畜实践的变化，大坝建设，森林砍伐，侵占野生动植物栖息地，气候变化，环境污染以及病原体引入新地区是导致传染病出现的一些因素。需要了解这些疾病出现的病原体的动态以及其宿主与环境之间的复杂和不断变化的关系才能潜在控制这些疾病。各种各样的人类和环境影响导致许多宿主 - 病原体系统发展并适应这些不断变化的影响，从而使控制更加困难。迫切需要我们对宿主病原体系统进化的理解有助于我们的理论研究。这项研究的目的是基于流行病学，遗传学和人口动态的原理开发，分析和模拟数学模型，将这些模型应用于宿主 - 病原体系统，并对特定的宿主病原体系统进行实验研究。在拟议的研究中开发的寄主人群模型专门应用于两栖群体。两栖动物人口的全球下降被认为是当今最紧迫，最神秘的环境问题之一。最近的证据表明，新兴疾病（病毒和真菌病原体）负责青蛙，蟾蜍和sal的大规模死亡。确实，最近在两栖动物中爆发的疾病爆发应受到严重关注，因为它们可能会在全球范围内表明环境变化，这可能威胁到许多生物。拟议的研究的主要部分涉及为期两年的领域和三年的实验室调查。实验研究的目的是评估南部高原上两种普通两栖动物的两种常见物种的两栖动物丰度，疾病患病率和免疫学特征。这项研究为两栖动物人口下降的未来研究奠定了基础。该赠款是根据DMS/NIGMS联合倡议提供的，以支持数学生物学领域的研究补助金。这是由国家科学基金会的数学科学系（DMS）和美国国立卫生研究院的国家一般医学科学研究所（NIGMS）赞助的。