WASTEWATER AND WATER ENVIRONMENT AS A POTENTIAL SOURCE OFFAECAL-ORAL TRANSMISSION OF SARS-COV-2 VIRUS

The world is facing the third wave of the SARS-CoV-2 virus pandemics, with over 118 million persons infected and over 2.6 million dead. In the past year, insights into the infection spread routes, including faecal-oral transmission due to untreated urban wastewater discharges containing the virus from excretions of infected persons. It has been also confirmed that the virus concentration in wastewater has a good correlation with the number of infected persons, particularly for a 14-day incidence, so that wastewater analysis provides a good insight into regional epidemiological situations and wastewater-based epidemiology (WBE) can be used as a sensitive parameter in the monitoring of epidemiological trends. This paper provides an overview of to-date research regarding the virus transmissionroutes, main virus sources in wastewater, load level in wastewater and environmental samples, virus survival in wastewater and environmental samples as well as techniques of virus removal from wastewater and its deactivation.

A colorimetric sandwich-type bioassay for SARS-CoV-2 using a hACE2-based affinity peptide pair.

The metallopeptidase angiotensin-converting enzyme 2 (ACE2) is the SARS-CoV-2 receptor required for viral entry based on its specific recognition of the spike protein receptor binding domain (S_RBD) on SARS-CoV-2. We constructed a human ACE2 (hACE2)-based peptide pair by ligating discontinuous key residues involved in the hACE2-S_RBD interaction. We firstly performed in silico simulations to identify a 12-mer and 15-mer peptide pair with capability to bind to the SARS-CoV-2 S_RBD via different binding sites. Then, the bio-layer interferometry validated the specific interactions between the peptides and S_RBD, with affinities at the nanomolar level. Lastly, we developed a colorimetric sandwich-type bioassay based on S_RBD-specific peptide-modified gold nanoparticles and found the colorimetric bioassay offered fast (<30 min), simple, and sensitive detection of S_RBD protein at levels as low as 0.01 nM (0.26 ng mL-1) in SARS-CoV-2. The linear signals ranging from 105 to 107 virus copies mL-1 were achieved in typical types of environmental waters spiked with lysed SARS-CoV-2 pseudovirus. The technology can serve as a beneficial supplement to the routine virus nucleic acid detection in environment media and wastewater treatment.

Concentration and Quantification of SARS-CoV-2 RNA in Wastewater Using Polyethylene Glycol-Based Concentration and qRT-PCR.

Wastewater-based epidemiology has become an important tool for the surveillance of SARS-CoV-2 outbreaks. However, the detection of viruses in sewage is challenging and to date there is no standard method available which has been validated for the sensitive detection of SARS-CoV-2. In this paper, we describe a simple concentration method based on polyethylene glycol (PEG) precipitation, followed by RNA extraction and a one-step quantitative reverse transcription PCR (qRT-PCR) for viral detection in wastewater. PEG-based concentration of viruses is a simple procedure which is not limited by the availability of expensive equipment and has reduced risk of disruption to consumable supply chains. The concentration and RNA extraction steps enable 900-1500× concentration of wastewater samples and sufficiently eliminates the majority of organic matter, which could inhibit the subsequent qRT-PCR assay. Due to the high variation in the physico-chemical properties of wastewater samples, we recommend the use of process control viruses to determine the efficiency of each step. This procedure enables the concentration and the extraction the DNA/RNA of different viruses and hence can be used for the surveillance of different viral targets for the comprehensive assessment of viral diseases in a community.

Beating the Bio-Terror Threat with Rapid Antimicrobial Susceptibility Testing.

A bioterror event using an infectious bacterium may lead to catastrophic outcomes involving morbidity and mortality as well as social and psychological stress. Moreover, a bioterror event using an antibiotic resistance engineered bacterial agent may raise additional concerns. Thus, preparedness is essential to preclude and control the dissemination of the bacterial agent as well as to appropriately and promptly treat potentially exposed individuals or patients. Rates of morbidity, death, and social anxiety can be drastically reduced if the rapid delivery of antimicrobial agents for post-exposure prophylaxis and treatment is initiated as soon as possible. Availability of rapid antibiotic susceptibility tests that may provide key recommendations to targeted antibiotic treatment is mandatory, yet, such tests are only at the development stage. In this review, we describe the recently published rapid antibiotic susceptibility tests implemented on bioterror bacterial agents and discuss their assimilation in clinical and environmental samples.

SARS-CoV-2 in Human Sewage and River Water from a Remote and Vulnerable Area as a Surveillance Tool in Brazil.

In the present study, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was monitored in environmental samples from rural and vulnerable areas (a presidio, worker accommodation units, and river waters upstream and downstream of a rural community) from Minas Gerais State region, Southern Brazil, in August 2020. The sampling was performed prior to official declaration of the coronavirus disease (COVID-19) cases in those sites. SARS-CoV-2 RNA was detected in the presidio and workers accommodation units (3.0 × 104 virus genome copies (GC)/mL and 4.3 × 104 GC/mL of sewage, respectively). While SARS-CoV-2 was not detected in the river water upstream of the rural community, SARS-CoV-2 RNA was detected in downstream river waters (1.1 × 102 SARS-CoV-2 GC/mL). The results obtained in this study highlight the utility of SARS-CoV-2 monitoring in wastewater and human sewage as a non-invasive early warning tool to support health surveillance in vulnerable and remote areas, particularly in development countries.

Environmental virus detection associated with asymptomatic SARS-CoV-2-infected individuals with positive anal swabs.

In the fight against the outbreak of COVID-19 in China, we treated some asymptomatic infected individuals. This study aimed to detect pathogens in biological and environmental samples of these asymptomatic infected individuals and analyse their association. Using a cross-sectional study design, we collected biological and environmental samples from 19 patients treated in the isolation ward of Nanjing No.2 Hospital. Biological samples included saliva, pharyngeal swabs, blood, anal swabs, and exhaled breath condensate. Swab samples from the ward environment included inside masks, outside masks, palm swabs, bedside handrails, bedside tables, cell phone screens, toilet cell phone shelves, toilet pads and toilet lids. We also obtained some samples from public areas. We used RT-PCR to detect pathogens and colloidal gold to detect antibodies. As results, 19 asymptomatic infected individuals participated in the survey, with 8 positives for pathogens and 11 positives only for antibodies. Three positive samples were detected from among 96 environmental samples, respectively, from a cell phone surface, a cell phone shelf and a bedside handrail. No positive samples were detected in the exhaled breath condensate in this work. All patients identified pathogens in the environment had positive anal swabs. There was a statistical association between positive anal swabs and positive environmental samples. The association of positive samples from the surrounding of asymptomatically infected patients with positive anal swabs suggested that patients might secrete the virus for a more extended period.