Anaerobic lagoon for treatment of dairy waste. Image by kjkolb. (CC BY-SA 3.0)
One of the results of the recent pandemic has been a breakthrough in medical science, especially with mRNA vaccines. There are also other areas where advances in scientific understanding have been made.
This includes an expansion of wastewater-based infectious disease surveillance systems designed to monitor and anticipate disease trends in communities. One limitation with this approach is where there is a population without sewerage (this is still a factor for some parts of the US)
To build on the progress made during the height of COVID-19, the US Centers for Disease Control and Prevention (CDC) launched the National Wastewater Monitoring System. As of September 2020, this initiative was intended to help coordinate and leverage wastewater surveillance efforts.
During the pandemic, the tests provided continuous information about where the virus was circulating and the degree of risk of exposure (as reported by Digital magazine “Coronavirus detection in wastewater helps evaluation of case count”).
The processes developed involve the analysis of markers in a wastewater treatment plant to assess a target disease. In terms of the coronavirus responsible for the pandemic, SARS-CoV-2, three different PCR assays were used to detect viral RNA. PCR is a reference to polymerase chain reaction, the method used to rapidly make millions or billions of copies of a specific genetic sample. This technique allows scientists take a very small sample of material (in this case, RNA extracted from a sewage sample, which has in turn been dumped by infected people) and amplify it to a large enough amount to study in detail.
A new report (“Wastewater-based disease surveillance for public health action”), issued in January 2023, reviews the usefulness of community-level wastewater monitoring during the pandemic and assesses its potential value for infectious disease control and prevention beyond COVID-19.
Too as continuous monitoring, evaluation of archived samples is also important for monitoring spread. Additionally, performing phylogenetic analyzes of viral sequences from current and archival samples helps scientists assess the degree of mutation of a given virus or other pathogen.
The report concludes that wastewater surveillance is and will continue to be a valuable component of infectious disease management. To help local governments build a scientific legacy, the report presents a vision for a national wastewater surveillance system that would track multiple pathogens simultaneously, including having the resources to detect emerging pathogens.
The report also recommends approaches to address privacy and ethical concerns and develop a more representative wastewater surveillance system.
However, for the vision to become a reality in the US, sustained federal funding is required along with the willingness of different agencies to coordinate and collaborate.