Wastewater-based epidemiology (WBE) is a well-established testing approach and regularly features in headlines when used to gauge illegal drug use in different parts of the world. The researchers, from Cranfield University and China’s Institute of Geochemistry, believe the same method can be used to detect levels of Covid-19 infection in communities. This could in term inform individual testing and help better track and fight the coronavirus.
"In the case of asymptomatic infections in the community or when people are not sure whether they are infected or not, real-time community sewage detection through paper analytical devices could determine whether there are Covid-19 carriers in an area to enable rapid screening, quarantine and prevention,” said Dr Zhugen Yang, lecturer in Sensor Technology at Cranfield Water Science Institute.
"If Covid-19 can be monitored in a community at an early stage through WBE, effective intervention can be taken as early as possible to restrict the movements of that local population, working to minimise the pathogen spread and threat to public health."
The simple paper testing device is folded and unfolded in steps to filter the nucleic acids of pathogens from wastewater samples, then a biochemical reaction with preloaded reagents detects whether the nucleic acid of SARS-CoV-2 – the virus behind the Covid-19 pandemic - is present. Results are visible to the naked eye, with a green circle indicating positive and a blue circle negative. The work is described in Environmental Science & Technology.
"We have already developed a paper device for testing genetic material in wastewater for proof-of-concept, and this provides clear potential to test for infection with adaption," Dr Yang continued.
"This device is cheap [costing less than £1] and will be easy to use for non-experts after further improvement. We foresee that the device will be able to offer a complete and immediate picture of population health once this sensor can be deployed in the near future."
Paper testing kits like this are easy to stack, store and transport and can be brought to market relatively quickly. Previously, Dr Yang has developed paper-based kits to successfully conduct tests for rapid veterinary diagnosis in India and for malaria in blood among rural populations in Uganda.