Bio-Rad Reads: Wastewater Edition 2.0

Welcome to another edition of Bio-Rad Reads! As we wrap up the month of August, rising levels of COVID-19 have brought wastewater-based epidemiology back in the headlines. Over the last few years, wastewater testing has been an integral part of research and public health surveillance aimed at curbing the spread of infectious disease. Sensitive detection methods like Droplet Digital PCR (ddPCR) technology have played a vital role in fueling these efforts and enabling early detection of potential outbreaks of COVID-19 and other infectious diseases.

In this newsletter, we’ll discuss:

• The past, present, and future of wastewater-based epidemiology
• Real-world experiences of researchers establishing a successful wastewater surveillance system
• What makes ddPCR technology an ideal tool for wastewater-based epidemiology

Wastewater-Based Epidemiology: Past, Present, and Future

Scientists have harnessed the predictive power of wastewater surveillance for public health efforts since the 1980s. The earliest wastewater-based epidemiology (WBE) programs were aimed at detecting “silent” outbreaks of polio. Because only about 1% of polio infections result in paralysis, researchers needed an effective way to detect community polio circulation as early as possible without waiting to observe clinically significant symptoms.

In the 2000s, WBE was applied to monitor population-level trends in alcohol, drug, and tobacco use over time without the limitations of stigma and healthcare access issues. It has also been a useful modality for tracking the evolution of antibiotic resistance mechanisms across diverse microorganisms with the goal of developing strategies to overcome them.

WBE’s real spotlight moment came in 2020 as public health officials raced to track and quantify the spread of SARS-CoV-2 at the community level while capturing symptomatic and asymptomatic cases alike. In September 2020, CDC established the National Wastewater Surveillance System (NWSS) , which works with local health departments to compile wastewater testing data from communities across the country. Monitoring through the NWSS has also proven useful in tracking the spread of other infectious diseases, including Mpox and Influenza A. Now, with respiratory virus season looming over the United States and an outbreak of Mpox recently declared a global public health emergency by WHO, vigilant infectious disease surveillance remains critical to minimizing spread and developing appropriate responses.

To learn more about the history and future of wastewater surveillance for public health, download our eBook, “The Past, Present, and Future of Wastewater-Based Epidemiology” .

Stories from the Front Lines of WBE

What does it take to set up a wastewater surveillance program in the middle of a global pandemic? A team of scientists from Colorado State University, led by Dr. Heather Pidcoke, developed a method to concentrate, extract, and analyze SARS-CoV-2 RNA from area wastewater samples using ddPCR technology. Samples were provided by local wastewater treatment plants or collected from sewers on the CSU campus.

Importantly, their “micro-surveillance” approach tracked viral load in samples from specific locations, including CSU dorms and off-campus housing facilities. In doing so, they could detect potential outbreaks early, allocate precious testing resources where they were most needed, and provide targeted intervention. Their story highlights the most powerful advantages of WBE for monitoring infectious disease and informing public health efforts.

Watch the webinar to hear their full story: https://www.youtube.com/watch?v=JfaZctg2G0A .

Sensitive Sewer Insights with ddPCR Technology

We know the sensitivity and precision of Droplet Digital PCR technology make it a valuable tool for countless applications, and WBE is no exception. While RT-PCR is also a common approach for wastewater pathogen detection, ddPCR technology offers some key advantages:

• Because ddPCR accurately quantifies individual viral molecules in each partitioned droplet of a sample, it can successfully detect viral load even when community infection rates are low. This is critical for early detection and intervention in a potential outbreak.
• Sewage samples contain a milieu of lipids and proteins that can interfere with RT-PCR analysis. ddPCR is less sensitive to these inhibitors than RT-PCR, enabling strong performance even when they’re present at high concentrations.
• ddPCR’s multiplexing capabilities are well-suited to accurately detecting and quantifying multiple pathogens or variants within a single sample. This is especially valuable for discerning rates of respiratory illnesses, such as influenza and respiratory syncytial virus, that have similar symptoms but can pose significant risks to vulnerable populations.

Learn more about the advantages of ddPCR technology for wastewater surveillance and explore WBE assay offerings here: https://info.bio-rad.com/wastewater-based-epidemiology-ddpcr.html .