Role of wildlife in the ecology of multihost pathogens

病原体感染多个宿主，特别是野生动物的能力，是人类和牲畜出现疾病的一个重要风险因素。了解多宿主群落中传染因子的动态对于减少对人类的疾病威胁至关重要，但我们往往缺乏关于野生动物在多宿主病原体生态中的作用的基本信息。我的研究计划的总体目标是建立对多宿主病原体系统的机制理解，以便为旨在控制影响人类和牲畜的传染病的疾病准备和预防策略提供科学依据。***本课题主要研究两种宿主-病原体系统：1)加拿大野生动物-家畜交界面引起人类细菌性肠炎的重要病原菌弯曲菌（Campylobacter）； 2)野生动物宿主和媒介中引起莱姆病的伯氏疏螺旋体（Borrelia burgdorferi）。虽然家畜是弯曲杆菌的主要宿主，但这种病原体在各种野生动物物种中也有很高的流行率。然而，野生动物在农场弯曲杆菌流行病学中的作用仍然不清楚，因为关于野生动物是否携带牲畜弯曲杆菌菌株的证据相互矛盾。我的第一个目标是a)确定野生动物在农场维持弯曲杆菌的作用，b)描述影响弯曲杆菌在野生动物中发生的环境和人口因素。***莱姆病系统的生态是复杂的，部分原因是蜱虫能够以几乎任何脊椎动物宿主为食，但宿主物种在通过整理来管理蜱虫负荷的能力和作为宿主的能力（即感染和传播伯氏疏螺旋体的能力）方面差异很大。因此，宿主生物多样性被认为是决定莱姆病传播和莱姆病对人类风险的关键因素。我的第二个目标是a)比较鸟类、哺乳动物和爬行动物作为亚成年蜱虫宿主和伯氏疏螺旋体潜在宿主的相对作用，b)评估野生动物宿主多样性对人类疾病风险的影响。***我提议的研究结合了宿主的实地研究、病原体的分子表征和统计建模，以便更好地了解病原体如何在野生动物种群中维持，并建立两个重要的多宿主病原体系统的传播动力学。*** ******

The ability of pathogens to infect multiple hosts, particularly wildlife, is an important risk factor for disease emergence in humans and livestock. Understanding the dynamics of infectious agents in multihost communities is essential for reducing disease threats to humans, yet we often lack even basic information about the role of wildlife in the ecology of multihost pathogens. The overall goal of my research program is to build a mechanistic understanding of multi-host pathogen systems in order to generate a scientific basis for disease preparedness and prevention strategies aimed at controlling infectious diseases affecting humans and livestock. *** This research proposal is focused on two host-pathogen systems: 1) Campylobacter, an important cause of bacterial enteritis in humans in Canada, at the wildlife-livestock interface, and 2) Borrelia burgdorferi, the causative agent of Lyme disease, in wildlife hosts and vectors. Although livestock are the primary reservoir of Campylobacter, this pathogen is also found at very high prevalence in a variety of wildlife species. However, the role of wildlife in the epidemiology of Campylobacter on farms remains unclear because there is conflicting evidence as to whether wildlife carry livestock strains of Campylobacter. My first objective is to a) determine the role of wildlife in the maintenance of Campylobacter on farms, and b) characterize the environmental and demographic factors affecting Campylobacter occurrence in wildlife. *** The ecology of the Lyme disease system is complex, due in part to the fact that the ticks are capable of feeding on almost any vertebrate host, but host species vary greatly in their ability to manage tick loads through grooming and in their competency as hosts (i.e., their ability to become infected with and transmit B. burgdorferi). For this reason, host biodiversity is thought to be critical in determining the spread of Lyme disease and Lyme disease risk to humans. My second objective is to a) compare the relative roles of birds, mammals, and reptiles as hosts for subadult ticks and as potential reservoirs of B. burgdorferi and b) assess the impact of wildlife host diversity on disease risk to humans. *** My proposed research combines field studies of hosts, molecular characterization of pathogens, and statistical modelling in order to better understand how pathogens are maintained in wildlife populations and to establish transmission dynamics in two important multihost pathogen systems. *** ******