This is another short “scientific opinion” paper, produced for inclusion in the recent Environmental Science and Technology virtual issue on the fate and behaviour of enveloped viruses in the environment. These scientific opinion pieces are non-peer reviewed, but are written by recognised experts in their field and should be viewed as a means to stimulating further discussion.
In this case, the authors are Kang Mao (Institute of Geochemistry Chinese Academy of Sciences) Hua Zhang (Institute of Geochemistry Chinese Academy of Sciences) and Zhugen Yang (Cranfield University, UK), and they ask the question “can a paper-based device trace COVID-19 sources with wastewater-based epidemiology?” This follows on from the discussion featured on this blog (and subsequently in global media) on the potential to monitor fragments on SARS-CoV-2 RNA in municipal sewage to ascertain patterns of infection in communities, -a concept known as wastewater-based epidemiology.
Current methods used for detection of SARS-CoV-2 are nucleic acid–based polymerase chain reaction (PCR) assays, which detect the presence of (at least fragments of) the RNA from the virus.
These authors propose using a wastewater-based epidemiology approach in developing “an early warning system and consequent effective intervention system”, incorporating a rapid analytical method for the on-site detection of viruses at wastewater collection points. They argue that the PCR method has a number of practical limitations preventing it from being ideal for such applications, including:
- Requirements for complicated sample handling in the laboratory,
- Employment of highly skilled personnel, and
- A period of data processing and analysis (4–6 h), not conducive to real-time monitoring of samples on location.
To overcome these limitations, the authors propose the development of a new approach based on paper analytical devices. Such paper analytical devices have been developed as tools for the rapid diagnosis of some pathogens and a table of examples are presented in the article.
These paper-based devices are said to be based on an inexpensive paper material, incorporating various functional areas, printed with a wax printer, and integrating each of the key processes for nucleic acid (e.g. RNA) testing. That is, there are functional areas dedicated to processes such as extraction of the nucleic acid, enrichment, purification, elution, amplification, and visual detection.
The testing process is said to be completed by folding of the paper-based device in different ways in different steps without the need of a pump or power supply. Although wastewater is a complex matrix, the authors argue that paper-based devices have shown the potential to detect pathogens in wastewater.
It is unclear how significant such a proposal could prove to be. However, wastewater based epidemiology for SARS-CoV-2 is clearly becoming a very hot topic in urban water industries around the world. A number of major discussions are currently taking place to seek out opportunities for effective research and international collaboration. Perhaps paper-based devices have some role to play in those discussions. In any case, it’s going to be a very fast moving field.
Mao K, Zhang H and Yang Z (2020) Can a Paper-Based Device Trace COVID-19 Sources with Wastewater-Based Epidemiology? Environmental Science & Technology.