Collaborative Research: Identifying the Flow and Control of Pathogens from the Land to the Sea: Tracking Toxoplasma from Cats to Sea Otters

本研究的主要目的是了解弓形虫从陆生宿主传播到受威胁的南方海獭种群的生态决定因素，并将这些数据用于预测模型，以评估宿主丰度、感染率、水管理、栖息地结构(陆地和水生)和猎物选择的变化的影响。研究和模型开发将集中在这种原生动物寄生虫上，因为弓形虫是南方海獭的主要死亡原因，而水獭是这种重要的人类病原体造成海洋污染的有价值的哨兵。这项综合研究集中在弓形虫感染和海獭死亡流行的两个沿海地点，包括三个组成部分，将陆地生态与土地利用模式联系起来，并最终与海獭生态联系起来。来自加州大学戴维斯分校、加州州立大学弗雷斯诺分校、生态系统研究所和不列颠哥伦比亚大学的研究人员将根据家猫和野生啮齿动物种群中感染的流行率预测卵囊对陆地环境的污染和接触弓形虫的风险。研究人员假设，水獭的风险存在明显的空间模式，因为陆地径流在沿海水域的特定位置形成了明确的区域，预计这些区域的卵囊密度很高。最后，他们建议研究个体水獭的饮食和活动是否可以预测由弓形虫感染引起的原虫脑炎暴露和死亡的风险。来自这三个组成部分的数据将使人们能够利用模拟模型评估替代控制策略的影响，以测试减少假定的风险因素是否会减少特定地点的弓形虫发病率和水獭的流行率。该项目在其多学科和综合方法方面是独一无二的--包括陆地和海洋生态学家、海洋学家、流行病学家和寄生虫学家，以调查陆地和水系统交界处的一种重要环境病原体的生态。就这项研究的更广泛影响而言，该项目强调研究生在研究和推广方面的培训。总体而言，4名博士生和2名硕士生将在研究和推广工作中接受指导。该模拟模型将允许评估不同的控制策略，以减少近岸海洋环境的病原体污染。这将有利于正在努力恢复的受到威胁的南部海獭数量，以及沿海地区的其他海洋生物和人类。海獭是能见度极高的旗舰物种，这为公众提供了一个独特的机会，让他们了解海陆界面和病原体污染。将扩大公共网站www.searotterresearch.org，以包括关于这项研究目标的具体信息，并以对公众友好的形式宣传研究结果，并专门为较年轻的学生(K-8)、土地和水资源管理人员以及猫主人提供互动部分。将通过沿海地区的宠物产品零售商和兽医向养猫的公众提供一本小册子，解释弓形虫病的风险，建议猫主人的最佳做法，以及减少环境中弓形虫暴露的方法。带有网址的海獭书签也将通过宠物产品零售商和高影响地区的学校免费提供。两个研究地点的高级人员和学生将组织和参加公众市政厅会议，向当地居民通报和讨论这项研究的理由、设计和结果。参与该项目的每一名研究生都将接受公共关系/演讲方面的培训，并将被要求每年至少在学校和高危社区的公开会议上作两次发言。此外，除了原创研究出版物外，学生们还将在国家科学会议上展示这项研究的成果。

ABSTRACTEF - 0525765The primary goal of this research is to understand the ecological determinants of transmission of the pathogen Toxoplasma gondii from terrestrial hosts to the threatened southern sea otter (Enhydra lutris nereis) population and to use these data in predictive models to evaluate the impact of changes in host abundance, infection prevalence, water management, habitat structure (terrestrial and aquatic) and prey selection. The study and model development will focus on this protozoan parasite because T. gondii is the major cause of death in southern sea otters, and otters serve as a valuable sentinel for marine pollution with this important human pathogen. Focusing on two coastal sites where T. gondii infections and mortality in sea otters are prevalent, this integrated study has three components that link terrestrial ecology to land use patterns and ultimately to sea otter ecology. Investigators from University of California at Davis, California State University at Fresno, Institute of Ecosystems Study, and University of British Columbia will predict terrestrial environmental contamination with oocysts and risk of exposure to T. gondii based on the prevalence of infection in domestic felids and wild rodent populations. The investigators hypothesize that there is a distinct spatial pattern of risk for otters because land runoff forms well-defined zones at specific locations in coastal waters, and high oocyst concentrations are expected in these zones. Finally, they propose to study whether individual otter diet and movements can predict the risk of exposure and death from protozoal encephalitis caused by T. gondii infection. Data from the three components will permit evaluating the impact of alternative control strategies using simulation modeling to test whether reduction of putative risk factors will reduce site-specific incidence and prevalence of T. gondii in otters. This project is unique in its multidisciplinary and comprehensive approach - incorporating terrestrial and marine ecologists, oceanographers, epidemiologists, and parasitologists to investigate the ecology of an important environmental pathogen at the interface of terrestrial and aquatic systems. In terms of the broader impacts of this study, this project emphasizes graduate student training in research and outreach. Overall, 4 Ph.D. and 2 Masters students will be mentored in research and outreach efforts. The simulation model will permit evaluation of different control strategies to reduce pathogen pollution of the near shore marine environment. This will benefit the threatened southern sea otter population that is struggling to recover, as well as other marine wildlife and humans in coastal areas. Sea otters are a flagship species with extremely high visibility, which provides a unique opportunity to inform the public about the land-sea interface and pathogen pollution. A public website www.seaotterresearch.org will be expanded to include specific information on the goals of this study and to publicize the findings in a public-friendly format with special interactive sections devoted to younger students (K-8), land and water resource managers, and cat owners. A brochure explaining risks of toxoplasmosis, suggested best practices for cat owners, and methods to reduce environmental exposure to T. gondii will be provided to the cat-owning public through pet product retailers and veterinarians in coastal areas. Sea otter bookmarks with the web address will also be provided at no cost through pet product retailers and schools in the high impact areas. Public town hall meetings will be organized and attended by senior personnel and students at both study sites to inform and discuss with local residents the rationale, design and findings of the study. Each of the graduate students involved in the project will be trained in public relations/speaking and will be required to make at least 2 presentations per year at schools and public meetings in high-risk communities. In addition, to original research publications, students will present the results of this research at national scientific conferences.