Researchers from the Spanish National Research Council (CSIC) and Valencia University (UV) have developed a molecular analysis system that can warn of the presence of SARS-CoV-2 (which causes the Covid-19 disease) in a community based on the study of its waste water.
The analysis system, which could be used as a method for epidemiologic monitoring, has been tested in Murcia (Spain) and in three treatment plants of the metropolitan area of Valencia. The analyses have shown that the disinfection treatments in these plants are efficient in removing the presence of the virus.
The new analysis system has been developed by researchers from two centres of the CSIC and a mixed centre of the UV and the CSIC. In Valencia, the analyses have been conducted by researchers of the Agrochemistry and Food Technology Institute (IATA, CSIC), headed by Gloria Sánchez and Walter Randazzo, and the UV, headed by Pilar Domingo-Calap and Rafael Sanjuán. The analyses in Murcia were conducted by the team of Sánchez and Randazzo, the IATA, alongside a team headed by Ana Allende and Pilar Truchado, from the Centre for Soil Science and Applied Biology of the Segura (CEBAS, CSIC).
In Murcia, the study was initiated by the Wastewater Treating and Purifying Entity of the Murcia Region (ESAMUR) in collaboration with other research centres from the IATA and CEBAS. “The research groups have been taking samples since 12 March and over 60 samples have been analysed in this time in different points of the six treatment stations of the region, including effluent water and the water resulting from the secondary treatment,” explains researcher Ana Allende, from the CEBAS. In first place, the objective was to determine whether there was presence of SARS-CoV-2 in the waste water and verify the efficacy of the disinfection treatments implemented in the treatment plants,” she adds.
In Valencia, these studies were conducted in collaboration with the wastewater treatment plants of Pinedo 1 and 2 and Quart-Benàger, which are dependant of the regional Department of Agriculture, Rural Development, Climatic Emergency and Ecologic Transition. The researchers are analysing more treatment plants of the Valencia Community, as well as samples gathered on different dates before the first patients came down with Covid-19 in Spain. “The goal is to establish this type of analysis as a method for epidemiologic monitoring. To detect changes in the presence of the genetic material of the virus in urban waste water throughout time and in different points of the Community will give us information on the prevalence of the virus among the population,” adds Pilar Domingo-Calap, researcher at the I2SysBio.
In order to conduct the study, the researchers applied methods that had previously been developed by the IATA group to detect the food borne virus. “The results obtained with molecular techniques to date, using recent samples, detected concentrations of around 100,000 copies of genetic material of the virus per litre of waste water,” highlights researcher Gloria Sánchez, from the IATA. Said levels are comparable to those of the USA. Other recent studies published in Holland and China have also detected the presence of SARS-CoV-2 in waste water. The study has verified that the disinfection treatment manages to remove the presence of the virus.