Prepare for an Outbreak: Environmental Surveillance as a Disease Monitoring Tool, and Interventions to Prevent Viral Transmission

The COVID-19 pandemic highlighted the critical need for enhanced outbreak preparedness against viruses. Key elements to this preparedness are robust disease surveillance systems and effective interventions to minimize disease transmission. While individual clinical testing is the conventional disease surveillance approach, environmental surveillance, such as monitoring wastewater or fomites, offers a valuable alternative. Environmental surveillance of viruses can offer timely warnings, provide evidence regarding the presence of a disease within a community, and help identify infection trends. Equally crucial is the identification and evaluation of nonpharmaceutical interventions (NPIs) that minimize transmission, such as personal hygiene practices. NPIs are particularly important during the early stages of an outbreak in the absence of pharmaceutical options. This dissertation aims to enhance outbreak preparedness against viruses by assessing environmental surveillance systems and quantifying the effectiveness of NPIs. Specifically, Chapter 2 examined wastewater monitoring across different sampling scales. We implemented a wastewater surveillance program for SARS-CoV-2 in a university campus at three different sampling levels (individual-building level, multiple-building level, and campus-level) within the same sewer network. The study ran in parallel to a comprehensive COVID-19 clinical screening program that included laboratory-confirmed asymptomatic cases for students. We found that concentrations of SARS-CoV-2 RNA in wastewater were positively correlated with COVID-19 case data at all levels, suggesting that wastewater monitoring may be a useful tool for tracking and investigating outbreaks at any of these levels. In Chapter 3, wastewater monitoring was employed to detect temporal and spatial variations in the predominance of virus subtypes. Using wastewater solids, we determined the predominant respiratory syncytial virus (RSV) subtype, RSV A or RSV B. We compared the predominant subtype in wastewater solids across multiple seasons, geographically distant metropolitan areas, and against clinical specimens. Our results showed that the predominant RSV subtype varied temporally but remained consistent spatially and between different sample types (wastewater and clinical samples). The results of this study suggest that wastewater holds promise for enhanced subtype surveillance, understanding subtype dynamics, and controlling RSV spread. Chapter 4 investigated viruses on fomites in the environment as both, an intermediary for infection and a health monitoring tool. In a systematic review and meta-analysis, we documented the occurrence of viruses on fomites in the environment and tested how certain variables affect positivity rate. We found that out of all 275 datasets identified, most had a low positivity rate (<15%), and identified variables that might influence positivity rates. These results highlight that viruses are present on fomites and, therefore, present a risk to human health, and that it is important to understand what factors affect positivity rates in order to effectively utilize fomites as a surveillance tool. Chapter 5 evaluated the efficacy of nonpharmaceutical interventions, specifically, less commonly known hygiene methods. In a laboratory volunteer study, we quantified the efficacy of ash and sand, alongside water, for varying amounts of time and compared them to WHO-preferred recommended agents (soap). Our results showed that handwashing for a full 20 seconds with any method resulted in log reduction values greater than 2-log removal, a commonly accepted threshold indicating good performance, for the viruses studied. It is essential to repeat these experiments in field conditions before recommending any agent tested exclusively in a laboratory. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]