An Evaluation of the Presence and Persistence of Viruses in Varying Water Matrices

A majority of sewage worldwide enters the environment untreated, creating a global health problem. Understanding and characterizing the presence and persistence of enteric viruses is critical to preserve public health, inform mitigation techniques, and feed risk assessment analyses. The main motivation of the work described in this dissertation is to characterize the inactivation kinetics under different conditions, specifically for human norovirus and Lassa virus. This dissertation investigates the presence and persistence of pathogenic viruses in water to inform best practices for water quality management. The four main objectives addressed in this dissertation were to (1) determine the persistence of viable human norovirus and associated RNA in different water sources, (2) understand the heat inactivation kinetics of human norovirus compared to surrogate MS2 bacteriophage, (3) evaluate the stability of infectious Lassa virus in wastewater and surfaces and chlorine inactivation, and (4) characterize the concentration efficacy of novel Nanotrap Microbiome Particles. Ultimately, the results from this research will improve risk assessments to protect public health and better wastewater-based epidemiology methods to track viral pathogens of interest.

The research presented in this dissertation addresses critical gaps in viral persistence, inactivation, and detection in various water environments and treatment scenarios, offering significant implications for public health. The work with viable human norovirus provides the first robust assessment of the persistence in different water matrices, filling a historical gap that was due to a lack of cell culture systems. This study, along with the results from the heat inactivation study, emphasizes the limitations of molecular methods in representing viable virus decay, and therefore, the associated infectious risk, which will guide future efforts in developing more accurate risk assessment models. Furthermore, the environmental persistence of Lassa virus results are the first of their kind, which will inform future strategies to mitigate environmental transmission in real-world scenarios.
The heat inactivation work for viable human norovirus and MS2 bacteriophage and the chemical disinfectant treatment with Lassa virus highlight effective treatment strategies for both viruses. These results can inform treatment protocols for heat inactivation and disinfection to safeguard public health. Using Nanotrap Microbiome Particles in wastewater as a viral concentration method underscores the potential of advanced concentration technologies in future wastewater surveillance workflows. The results provides a pathway for optimizing surveillance pipelines, ultimately improving our ability to monitor and respond to viral pathogen spread throughout our communities. Together, the findings of this dissertation offers a comprehensive framework to improve environmental monitoring, public health interventions, and viral risk assessments and management strategies.

全球大部分污水未经处理即排入环境，构成了一个全球性健康问题。了解并表征肠道病毒的存在与持久性，对于维护公众健康、指导缓解技术研发以及为风险评估分析提供数据支撑至关重要。本论文所述研究的主要动机是表征不同条件下的灭活动力学，具体针对人诺如病毒（human norovirus）和拉沙病毒（Lassa virus）。本论文研究了水中致病性病毒的存在与持久性，旨在为水质管理的最佳实践提供指导。本论文的四个主要目标为：(1) 确定不同水源中具有活性的人诺如病毒（human norovirus）及其相关RNA的持久性；(2) 了解人诺如病毒与替代病毒MS2噬菌体（MS2 bacteriophage）相比的热灭活动力学；(3) 评估具有感染性的拉沙病毒（Lassa virus）在废水和表面的稳定性及氯灭活效果；(4) 表征新型Nanotrap Microbiome Particles的浓缩效能。最终，本研究结果将改进风险评估以保护公众健康，并优化基于废水的流行病学方法以追踪目标病毒性病原体。

本论文所述研究填补了不同水环境和处理场景下病毒持久性、灭活及检测领域的关键空白，对公众健康具有重要意义。针对具有活性的人诺如病毒的研究首次对其在不同水基质中的持久性进行了可靠评估，填补了因缺乏细胞培养系统而长期存在的空白。本研究与热灭活研究的结果共同强调了分子方法在表征活性病毒衰减（进而反映相关感染风险）方面的局限性，这将为未来开发更准确的风险评估模型提供指导。此外，拉沙病毒环境持久性的研究结果属首次报道，将为未来在实际场景中缓解环境传播的策略提供参考。

针对具有活性的人诺如病毒和MS2噬菌体的热灭活研究，以及针对拉沙病毒的化学消毒剂处理研究，凸显了针对这两种病毒的有效处理策略。这些结果可为热灭活和消毒处理方案提供参考，以保障公众健康。将Nanotrap Microbiome Particles用作废水中病毒浓缩方法，凸显了先进浓缩技术在未来废水监测流程中的潜力。研究结果为优化监测流程提供了路径，最终提升我们监测和应对社区内病毒性病原体传播的能力。综上，本论文的研究结果提供了一个全面框架，以改进环境监测、公共卫生干预措施以及病毒性风险评估与管理策略。