Copper Nanostructured biohybrid material as broad-spectrum antiviral agent and its application as coating surface material (preprint)

Respiratory pathogens kill more people than any other infectious agent each year worldwide. The development of novel economically-friendly, sustainable and highly efficient materials against viruses is a major challenge. Here we describe a nanostructured material composed of very small crystalline phosphate copper nanoparticles synthesized based on a new biohybrid technology that employs the use of a biological agent for its formation. This aqueous and room temperature stable material showed high virucidal activity against different viruses, including SARS-CoV-2. In addition, this new material has been successfully scaled-up and has been shown to have multiple applications as a coating agent on different surfaces of different composition (cotton, polyester, cellulose, paint, etc.). Interestingly, this nanomaterial showed antimicrobial-properties for the manufacture of antiviral face masks, maintaining high virucidal efficacy and stability, even after several washing cycles allowing its reuse.

Reliability of Wastewater Analysis for Monitoring COVID-19 Incidence Revealed by a Long-Term Follow-Up Study (preprint)

Background: Wastewater-based epidemiology has been used for monitoring human activities and waterborne pathogens. Although wastewaters can also be used for tracking SARS-CoV-2 at the population level, the reliability of this approach remains to be established, especially for early warning of outbreaks.Methods: We collected 377 samples from different treatment plants processing wastewaters of >1 million inhabitants in Valencia, Spain, between April 2020 and March 2021. Samples were cleaned, concentrated, and subjected to RT-qPCR to determine SARS-CoV-2 concentrations. These data were compared with cumulative disease notification rates over 7 and 14 day periods.Results: We amplified SARS-CoV-2 RNA in 75% of the RT-qPCRs, with an estimated detection limit of 100 viral genome copies per liter (gc/L). SARS-CoV-2 RNA concentration correlated strongly with disease notification rates over 14-day periods (Pearson r = 0·962, P < 0·001). A concentration >1000 gc/L showed >95% sensitivity and specificity as an indicator of more than 25 new cases per 100,000 inhabitants. Albeit with slightly higher uncertainty, these figures were reproduced using a 7-day period. Time series were similar for wastewaters data and declared cases, but wastewater RNA concentrations exhibited transient peaks that were not observed in declared cases and preceded major outbreaks by several weeks.Interpretation: Wastewater analysis provides a reliable tool for monitoring COVID-19, particularly at low incidence values, and is not biased by asymptomatic cases. Moreover, this approach might reveal previously unrecognized features of COVID-19 transmission.Funding Information: Conselleria d´Agricultura, Desenvolupament Rural, Emergencia Climàtica i Transició Ecològica of the Generalitat Valenciana (project OTR2020-20593SUBDI), Instituto de Salud Carlos III (FONDO-COVID19 COV20/00210), CSIC (Salud Global CSIC 202020E292), and Ministerio de Ciencia e Innovación (Ramón y Cajal contract, Call 2019).Declaration of Interests: We declare no competing interests.

Reliability of wastewater analysis for monitoring COVID-19 incidence revealed by a long-term follow-up study (preprint)

Background: Wastewater-based epidemiology has been used for monitoring human activities and waterborne pathogens. Although wastewaters can also be used for tracking SARS-CoV-2 at the population level, the reliability of this approach remains to be established, especially for early warning of outbreaks. Methods: We collected 377 samples from different treatment plants processing wastewaters of >1 million inhabitants in Valencia, Spain, between April 2020 and March 2021. Samples were cleaned, concentrated, and subjected to RT-qPCR to determine SARS-CoV-2 concentrations. These data were compared with cumulative disease notification rates over 7 and 14 day periods. Results: We amplified SARS-CoV-2 RNA in 75% of the RT-qPCRs, with an estimated detection limit of 100 viral genome copies per liter (gc/L). SARS-CoV-2 RNA concentration correlated strongly with disease notification rates over 14-day periods (Pearson r = 0.962, P < 0.001). A concentration >1000 gc/L showed >95% sensitivity and specificity as an indicator of more than 25 new cases per 100,000 inhabitants. Albeit with slightly higher uncertainty, these figures were reproduced using a 7-day period. Time series were similar for wastewaters data and declared cases, but wastewater RNA concentrations exhibited transient peaks that were not observed in declared cases and preceded major outbreaks by several weeks. Interpretation: Wastewater analysis provides a reliable tool for monitoring COVID-19, particularly at low incidence values, and is not biased by asymptomatic cases. Moreover, this approach might reveal previously unrecognized features of COVID-19 transmission.

Lack of evidence for infectious SARS-CoV-2 in feces and sewage (preprint)

The SARS-CoV-2 coronavirus is a respiratory virus whose primary route of transmission is airborne. However, it has been shown that the virus can replicate in gastrointestinal cells, can be excreted in feces, and can reach sewage systems. Although viral RNA is known to be found in patient feces and sewage, little is known about the possible fecal-oral transmission of the coronavirus. Determining the presence of infective viral particles in feces and sewage is necessary to take adequate control measures and to discover new routes of coronavirus transmission. Here, we analyzed feces and urine of COVID-19 patients and wastewater samples at the time of high prevalence in the region under study, both by molecular methods and cell culture. The results obtained do not evidence the presence of infective viral particles, although larger-scale efforts are needed to elucidate whether the fecal-oral transmission should be considered as a route of SARS-CoV-2 transmission.

Metropolitan Wastewater Analysis for COVID-19 Epidemiological Surveillance (preprint)

Background: The COVID-19 disease, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a rapidly emerging pandemic which has enforced extreme containment measures worldwide. In the absence of a vaccine or efficient treatment, cost-effective epidemiological surveillance strategies are urgently needed. Methods: Here, we have used RT-qPCR for SARS-CoV-2 detection in a series of longitudinal metropolitan wastewaters samples collected during the earliest stages of the epidemic in the Region of Valencia, Spain. Results: We were able to consistently detect SARS-CoV-2 RNA in samples taken when communicated cases in that region were only incipient. We also find that the wastewater viral RNA context increased rapidly and anticipated the subsequent ascent in the number of declared cases. Interpretation: Our results strongly suggest that the virus was undergoing community transmission earlier than previously believed, and show that wastewater analysis is a sensitive and cost-effective strategy for COVID-19 epidemiological surveillance. Routine implementation of this surveillance tool would significantly improve our preparedness against new or re-occurring viral outbreaks.