Inside the emerging science of wastewater surveillance

Data generated by wastewater surveillance is helping public health officials to better understand the extent of COVID-19 infections in communities.

In a collaborative effort, researchers are studying samples of wastewater to look for the presence of gene copies/fragments of the virus that causes COVID-19. This novel approach is named Wastewater Based Epidemiology (WBE).

What is WBE and how is it used for COVID-19 surveillance?

• “Wastewater,” also referred to as “sewage,” includes water from household/building use (i.e., toilets, showers, sinks) that can contain human fecal waste, as well as water from non-household sources (i.e., rainwater and industrial use)
• The basic premise of WBE is that community wastewater represents an unbiased snapshot of the population’s health and lifestyle habits
• Wastewater can be tested for genetic material (RNA) from SARS-CoV-2, the virus that causes COVID-19.
• Data from samples gathered in sewage collection systems’ raw wastewater may provide an early warning of disease occurrence in a community and possibly an estimation of the disease prevalence

Although WBE is a relatively new paradigm, wastewater testing has been successfully used as a method for early detection of other diseases, such as polio. It is considered a complementary approach for current disease surveillance systems and an early warning system for disease outbreaks. The concept is primarily based upon the extraction, detection, and subsequent analysis and interpretation of chemical and/or biological compounds and has been used as a research tool to assess illicit drug use, antibiotic resistance prevalence, and infectious diseases occurrence.

Many groups are currently trying to correlate the SARS-CoV-2 RNA detection in wastewater to number of cases in particular community. Back-calculating from the amount of viral RNA in wastewater to actual cases poses a lot of challenges, mostly due the uncertainty about multiple factors, such as the percentage of asymptomatic cases in population, magnitude of virus shedding, virus survival in the collection system, and wastewater flow rates.

Researchers at universities worldwide are exploring the use of wastewater-based epidemiology for coronavirus surveillance in communities. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ribonucleic acid (RNA) has been detected by numerous researchers in feces of both symptomatic and asymptomatic patients. Additional reports confirm the survival of the virus outside of the body for few hours to days, depending on the wastewater temperature, and its detection in municipal wastewater treatment plants. Community wide monitoring could help in detecting decreasing or increasing trend of the disease in particular region, which could better inform policies.

Despite the multiple challenges, researchers are exchanging ideas and collaborating to help in coronavirus surveillance. Once fully developed, WBE might become routine tool in public health protection.

Research publications: Explore the COVID-19 WBE Publications and Pre-prints

Selected Publications:

W. Ahmed, N. Angel, J. Edson, et al., First confirmed detection of SARS-CoV-2 in untreated wastewater in Australia: A proof of concept for the wastewater surveillance of COVID-19 in the community, Science of the Total Environment (2020), https://doi.org/10.1016/j.scitotenv.2020.138764