SARS-CoV-2 spillover into hospital outdoor environments.

Facing the ongoing coronavirus infectious disease-2019 (COVID-19) pandemic, many studies focus on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in indoor environment, on solid surface or in wastewater. It remains unclear whether SARS-CoV-2 can spill over into outdoor environments and impose transmission risks to surrounding people and communities. In this study, we investigated the presence of SARS-CoV-2 by measuring viral RNA in 118 samples from outdoor environment of three hospitals in Wuhan. We detected SARS-CoV-2 in soils (205-550 copies/g), aerosols (285-1,130 copies/m3) and wastewaters (255-18,744 copies/L) in locations close to hospital departments receiving COVID-19 patients or in wastewater treatment sectors. These findings revealed a significant viral spillover in hospital outdoor environments that was possibly caused by respiratory droplets from patients or aerosolized particles from wastewater containing SARS-CoV-2. In contrast, SARS-CoV-2 was not detected in other areas or on surfaces with regular implemented disinfection. Soils may behave as viral warehouse through deposition and serve as a secondary source spreading SARS-CoV-2 for a prolonged time. For the first time, our findings demonstrate that there are high-risk areas out of expectation in hospital outdoor environments to spread SARS-CoV-2, calling for sealing of wastewater treatment unit and complete sanitation to prevent COVID-19 transmission risks.

Ultra-fast and onsite interrogation of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in waters via surface enhanced Raman scattering (SERS).

The outbreak of coronavirus infectious disease-2019 (COVID-19) pneumonia challenges the rapid interrogation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in human and environmental samples. In this study, we developed an assay using surface enhanced Raman scattering (SERS) coupled with multivariate analysis to detect SARS-CoV-2 in an ultra-fast manner without any pretreatment (e.g., RNA extraction). Using silver-nanorod SERS array functionalized with cellular receptor angiotensin-converting enzyme 2 (ACE2), we obtained strong SERS signals of ACE2 at 1032, 1051, 1089, 1189, 1447 and 1527 cm-1. The recognition and binding of receptor binding domain (RBD) of SARS-CoV-2 spike protein on SERS assay significantly quenched the spectral intensities of most peaks and exhibited a shift from 1189 to 1182 cm-1. On-site tests on 23 water samples with a portable Raman spectrometer proved its accuracy and easy-operation for spot detection of SARS-CoV-2 to evaluate disinfection performance, explore viral survival in environmental media, assess viral decay in wastewater treatment plant and track SARS-CoV-2 in pipe network. Our findings raise a state-of-the-art spectroscopic tool to screen and interrogate viruses with RBD for human cell entry, proving its feasibility and potential as an ultra-fast detection tool for wastewater-based epidemiology.

Potential spreading risks and disinfection challenges of medical wastewater by the presence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) viral RNA in septic tanks of Fangcang Hospital.

The outbreak of coronavirus infectious disease-2019 (COVID-19) pneumonia raises the concerns of effective deactivation of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in medical wastewater by disinfectants. In this study, we evaluated the presence of SARS-CoV-2 viral RNA in septic tanks of Wuchang Cabin Hospital and found a striking high level of (0.5-18.7) × 103 copies/L after disinfection with sodium hypochlorite. Embedded viruses in stool particles might be released in septic tanks, behaving as a secondary source of SARS-CoV-2 and potentially contributing to its spread through drainage pipelines. Current recommended disinfection strategy (free chlorine ≥0.5 mg/L after at least 30 min suggested by World Health Organization; free chlorine above 6.5 mg/L after 1.5-h contact by China Centers for Disease Control and Prevention) needs to be reevaluated to completely remove SARS-CoV-2 viral RNA in non-centralized disinfection system and effectively deactivate SARS-CoV-2. The effluents showed negative results for SARS-CoV-2 viral RNA when overdosed with sodium hypochlorite but had high a level of disinfection by-product residuals, possessing significant ecological risks.