Milan, May 25 (beraking latest news Salute) – In the sewers flows precious material to photograph not only the habits of the citizens who feed the waters, from the consumption of drugs to the use of drugs, but also the progress of the Covid-19 epidemic. Anticipating the curve by up to 2 weeks compared to traditional monitoring techniques. This is demonstrated by a study conducted in Lombardy during the first pandemic wave, published on the ‘medRxiv’ preprint platform by scientists from the ‘Mario Negri’ Institute for Pharmacological Research Irccs, Department of Environment and Health, and the State University of Milan, Department of Sciences biomedical for health.
The authors of the work, conducted with the participation of the Lombardy Region, followed the evolution of Covid-19 looking for the coronavirus Sars-CoV-2 in urban wastewater through “an innovative approach called ‘wastewater epidemiology’, explain from ‘Mario Negri ‘and Statale announcing the results of the study, “first in Italy for the number of samples analyzed”: the data prove “the reliability of wastewater epidemiology as a tool for monitoring the epidemic trend of the virus in the population, able to to bring forward the trend of the epidemic curve by 7-14 days with respect to existing surveillance systems “.
The research involved 8 Lombard cities, selected from the areas most affected by the first wave of Covid-19: Bergamo, Brembate, Ranica, Brescia, Cremona, Crema, Lodi and Milan. In their inlet manifolds, 107 samples were taken between the end of March and mid-June 2020. Viral RNA was detected in 65, equal to 61% of the total, “one of the highest percentages of positivity among the studies conducted in other European and non-European countries in the same period”. Spikes of 80% were found in the Bergamo area, the epicenter of the first wave of Covid.
The highest percentages of positive samples were found, as well as in the Bergamo area (80%), in the Brescia area (77%) – the authors report – while lower levels were found in the Cremona area (58%) . The highest viral loads, which reflect a greater number of cases, were always observed in the Bergamo area (in Brembate and Ranica) and in Lodi (province to which the Codogno of ‘patient one’ belongs) in the period March-April 2020, for then decrease in the following months in conjunction with the measures of the first lockdown. In mid-June 2020, the wastewater of all investigated cities tested negative for Sars-CoV-2. The viral load profile measured in urban waste was found to be comparable with the number of active cases recorded in the same area.
The collaboration between the two groups, Irccs Mario Negri and the University of Milan, was born at the beginning of the pandemic – the Institute and the university recall in a note – and led to the development of an effective methodology for the detection of Sars-CoV-2 in city wastewater, which has been applied regionally. The analysis is based on the concentration of viral RNA from urban wastewater, and on the subsequent extraction and molecular analysis of RNA using real time PCR technology. The research activity continued with the examination of the epidemic profiles of the successive waves of Covid-19, autumn 2020 and winter-spring 2021, and the results will be available shortly.
The studies will now continue in the context of a Lombard network for the epidemiological surveillance of urban wastewater, promoted by the Region, and of the national network (Sari) promoted by the Higher Institute of Health (Iss). In fact, precisely for the monitoring of waste water, the recently approved Dl Sostegni Bis provided for a loan of almost 6 million euros with the aim of controlling the ‘moves’ of Sars-CoV-2 and its variants.
“The Mario Negri Institute – underlines Ettore Zuccato, head of the laboratory of the Environment and Health Department of the IRCCS founded and chaired by Silvio Garattini – developed the innovative approach called wastewater epidemiology in 2005 to estimate the consumption of substances such as abuse, alcohol and drugs in the population by analyzing urinary metabolites in untreated urban wastewater. Last year we immediately worked to develop a new application linked to the analysis of viruses in urban wastewater “.
“The State University of Milan – underline the professors Sandro Binda and Elena Pariani, engaged in the integrated surveillance network Covid-19 in Lombardy – has been dealing with environmental virological surveillance for over a decade, ie the analysis of urban wastewater collected at the entrance of a purifier to identify the introduction and distribution of viruses eliminated from the fecal tract, including enteroviruses “.
“As demonstrated by the present study – comments Sara Castiglioni of Mario Negri – virological surveillance of urban wastewater has great potential for use, since it allows to obtain a profile of the infections, including at the same time the symptomatic and asymptomatic infections of an entire population”. A strategy that according to the scientists will also be useful in the post-Covid era: “The methodology developed – they assure – represents a ready-to-use tool for monitoring any other viruses with epidemic / pandemic potential that could arise in the future”.