Coronavirus (SARS-CoV-2) in the environment: Occurrence, persistence, analysis in aquatic systems and possible management

The comparison of decay rates of infectious SARS-CoV-2 and viral RNA in environmental waters and wastewater

Understanding the decay characteristics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater and ambient waters is important for multiple applications including assessment of risk of exposure associated with handling wastewater samples, public health risk associated with recreation in wastewater polluted ambient waters and better understanding and interpretation of wastewater-based epidemiology (WBE) results. We evaluated the decay rates of infectious SARS-CoV-2 and viral RNA in wastewater and ambient waters under temperature regimes representative of seasonal fluctuations. Infectious virus was seeded in autoclaved primary wastewater effluent, final dechlorinated wastewater effluent, lake water, and marine water at a final concentration of 6.26 ± 0.07 log10 plaque forming units per milliliter. Each suspension was incubated at either 4°, 25°, and 37 °C. Samples were initially collected on an hourly basis, then approximately every other day for 15 days. All samples were analyzed for infectious virus via a plaque assay using the Vero E6 cell line, and viral gene copy levels were quantified with the US CDC's N1 and N2 reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) assays. The infectious virus decayed significantly faster (p ≤ 0.0214) compared to viral RNA, which persisted for the duration of the study irrespective of the incubation conditions. The initial loss (within 15 min of seeding) as well as decay of infectious SARS-CoV-2 was significantly faster (p ≤ 0.0387) in primary treated wastewater compared to other water types, but viral RNA did not degrade appreciably in this matrix until day 15. Overall, temperature was the most important driver of decay, and after 24 h, no infectious SARS-CoV-2 was detected at 37 °C in any water type. Moreover, the CDC N2 gene assay target decayed significantly (p ≤ 0.0174) faster at elevated temperatures compared to CDC N1, which has important implications for RT-qPCR assay selection for WBE approach.

Cold atmospheric plasma can effectively disinfect SARS-CoV-2 in the wastewater

COVID-19 is currently pandemic and the detection of SARS-CoV-2 variants in wastewater is causing widespread concern. Herein, cold atmospheric plasma (CAP) is proposed as a novel wastewater disinfection technology that effectively inactivates SARS-CoV-2 transcription- and replication-competent virus-like particles, coronavirus GX_P2V, pseudotyped SARS-CoV-2 variants, and porcine epidemic diarrhoea virus in a large volume of water within 180 s (inhibition rate > 99%). Further, CAP disinfection did not adversely affect the viability of various human cell lines. It is identified that CAP produced peroxynitrite (ONOO-), ozone (O3), superoxide anion radicals (O2 -), and hydrogen peroxide (H2O2) as the major active substances for coronavirus disinfection. Investigation of the mechanism showed that active substances not only reacted with the coronavirus spike protein and affected its infectivity, but also destroyed the nucleocapsid protein and genome, thus affecting virus replication. This method provides an efficient and environmentally friendly strategy for the elimination of SARS-CoV-2 and other coronaviruses from wastewater.

Interaction Between SARS-CoV-2 Spike Protein S1 Subunit and Oyster Heat Shock Protein 70

There is growing evidence that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contaminates the marine environment and is bioaccumulated in filter-feeding shellfish. Previous study shows the Pacific oyster tissues can bioaccumulate the SARS-CoV-2, and the oyster heat shock protein 70 (oHSP70) may play as the primary attachment receptor to bind SARS-CoV-2's recombinant spike protein S1 subunit (rS1). However, detailed information about the interaction between rS1 and oHSP70 is still unknown. In this study, we confirmed that the affinity of recombinant oHSP70 (roHSP70) for rS1 (KD = 20.4 nM) is comparable to the receptor-binding affinity of rACE2 for rS1 (KD = 16.7 nM) by surface plasmon resonance (SPR)-based Biacore and further validated by enzyme-linked immunosorbent assay (ELISA). Three truncated proteins (roHSP70-N/C/M) and five mutated proteins (p.I229del, p.D457del, p.V491_K495del, p.K556I, and p.ΣroHSP70) were constructed according to the molecular docking results. All three truncated proteins have significantly lower affinity for rS1 than the full-length roHSP70, indicating that all three segments of roHSP70 are involved in binding to rS1. Further, the results of SPR and ELISA showed that all five mutant proteins had significantly lower affinity for rS1 than roHSP70, suggesting that amino acids at these sites are involved in binding to rS1. This study provides a preliminary theoretical basis for the bioaccumulation of SARS-CoV-2 in oyster tissues or using roHSP70 as the capture unit to selectively enrich virus particles for detection.

Isorhamnetin: what is the in vitro evidence for its antitumor potential and beyond?

Isorhamnetin (ISO) is a phenolic compound belonging to flavonoid family, showcasing important in vitro pharmacological activities such as antitumor, anti-inflammation, and organ protection. ISO is predominantly extracted from Hippophae rhamnoides L. This plant is well-known in China and abroad because of its "medicinal and food homologous" characteristics. As a noteworthy natural drug candidate, ISO has received considerable attention in recent years owing to its low cost, wide availability, high efficacy, low toxicity, and minimal side effects. To comprehensively elucidate the multiple biological functions of ISO, particularly its antitumor activities and other pharmacological potentials, a literature search was conducted using electronic databases including Web of Science, PubMed, Google Scholar, and Scopus. This review primarily focuses on ISO's ethnopharmacology. By synthesizing the advancements made in existing research, it is found that the general effects of ISO involve a series of in vitro potentials, such as antitumor, protection of cardiovascular and cerebrovascular, anti-inflammation, antioxidant, and more. This review illustrates ISO's antitumor and other pharmacological potentials, providing a theoretical basis for further research and new drug development of ISO.

Porcine Epidemic Diarrhea Virus, Surrogate for Coronavirus Decay Measurement in French Coastal Waters and Contribution to Coronavirus Risk Evaluation

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in infected patients mainly displays pulmonary and oronasal tropism; however, the presence of the virus has also been demonstrated in the stools of patients and consequently in wastewater treatment plant effluents, raising the question of the potential risk of environmental contamination (such as seawater contamination) through inadequately treated wastewater spillover into surface or coastal waters even if the environmental detection of viral RNA alone does not substantiate risk of infection. Therefore, here, we decided to experimentally evaluate the persistence of the porcine epidemic diarrhea virus (PEDv), considered as a coronavirus representative model, in the coastal environment of France. Coastal seawater was collected, sterile-filtered, and inoculated with PEDv before incubation for 0 to 4 weeks at four temperatures representative of those measured along the French coasts throughout the year (4, 8, 15, and 24°C). The decay rate of PEDv was determined using mathematical modeling and was used to determine the half-life of the virus along the French coast in accordance with temperatures from 2000 to 2021. We experimentally observed an inverse correlation between seawater temperature and the persistence of infectious viruses in seawater and confirm that the risk of transmission of infectious viruses from contaminated stool in wastewater to seawater during recreational practices is very limited. The present work represents a good model to assess the persistence of coronaviruses in coastal environments and contributes to risk evaluation, not only for SARS-CoV-2 persistence, but also for other coronaviruses, specifically enteric coronaviruses from livestock. IMPORTANCE The present work addresses the question of the persistence of coronavirus in marine environments because SARS-CoV-2 is regularly detected in wastewater treatment plants, and the coastal environment, subjected to increasing anthropogenic pressure and the final receiver of surface waters and sometimes insufficiently depurated wastewater, is particularly at risk. The problem also arises in the possibility of soil contamination by CoV from animals, especially livestock, during manure application, where, by soil impregnation and runoff, these viruses can end up in seawater. Our findings are of interest to researchers and authorities seeking to monitor coronaviruses in the environment, either in tourist areas or in regions of the world where centralized systems for wastewater treatment are not implemented, and more broadly, to the scientific community involved in "One Health" approaches.

SARS-CoV-2 in the environment: Contamination routes, detection methods, persistence and removal in wastewater treatment plants

The present study reviewed the occurrence of SARS-CoV-2 RNA and the evaluation of virus infectivity in feces and environmental matrices. The detection of SARS-CoV-2 RNA in feces and wastewater samples, reported in several studies, has generated interest and concern regarding the possible fecal-oral route of SARS-CoV-2 transmission. To date, the presence of viable SARS-CoV-2 in feces of COVID-19 infected people is not clearly confirmed although its isolation from feces of six different patients. Further, there is no documented evidence on the infectivity of SARS-CoV-2 in wastewater, sludge and environmental water samples, although the viral genome has been detected in these matrices. Decay data revealed that SARS-CoV-2 RNA persisted longer than infectious particle in all aquatic environment, indicating that genome quantification of SARS-CoV-2 does not imply the presence of infective viral particles. In addition, this review also outlined the fate of SARS-CoV-2 RNA during the different steps in the wastewater treatment plant and focusing on the virus elimination along the sludge treatment line. Studies showed complete removal of SARS-CoV-2 during the tertiary treatment. Moreover, thermophilic sludge treatments present high efficiency in SARS-CoV-2 inactivation. Further studies are required to provide more evidence with respect to the inactivation behavior of infectious SARS-CoV-2 in different environmental matrices and to examine factors affecting SARS-CoV-2 persistence.

A critical assessment of SARS-CoV-2 in aqueous environment: Existence, detection, survival, wastewater-based surveillance, inactivation methods, and effective management of COVID-19

In early January 2020, the causal agent of unspecified pneumonia cases detected in China and elsewhere was identified as a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was the major cause of the COVID-19 outbreak. Later, the World Health Organization (WHO) proclaimed the COVID-19 pandemic a worldwide public health emergency on January 30, 2020. Since then, many studies have been published on this topic. In the present study, bibliometric analysis has been performed to analyze the research hotspots of the coronavirus. Coronavirus transmission, detection methods, potential risks of infection, and effective management practices have been discussed in the present review. Identification and quantification of SARS-CoV-2 viral loads in various water matrices have been reviewed. It was observed that the viral shedding through urine and feces of COVID-19-infected patients might be a primary mode of SARS-CoV-2 transmission in water and wastewater. In this context, the present review highlights wastewater-based epidemiology (WBE)/sewage surveillance, which can be utilized as an effective tool for tracking the transmission of COVID-19. This review also emphasizes the role of different disinfection techniques, such as chlorination, ultraviolet irradiation, and ozonation, for the inactivation of coronavirus. In addition, the application of computational modeling methods has been discussed for the effective management of COVID-19.

Bioaccumulation Pattern of the SARS-CoV-2 Spike Proteins in Pacific Oyster Tissues

There is mounting evidence of the contamination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the sewage, surface water, and even marine environment. Various studies have confirmed that bivalve mollusks can bioaccumulate SARS-CoV-2 RNA to detectable levels. However, these results do not provide sufficient evidence for the presence of infectious viral particles. To verify whether oysters can bind the viral capsid and bioaccumulate the viral particles, Pacific oysters were artificially contaminated with the recombinant SARS-CoV-2 spike protein S1 subunit (rS1). The bioaccumulation pattern of the rS1 in different tissues was investigated by immunohistological assays. The results revealed that the rS1 was bioaccumulated predominately in the digestive diverticula. The rS1 was also present in the epithelium of the nondigestive tract tissues, including the gills, mantle, and heart. In addition, three potential binding ligands, including angiotensin-converting enzyme 2 (ACE 2)-like substances, A-type histo-blood group antigen (HBGA)-like substances, and oyster heat shock protein 70 (oHSP 70), were confirmed to bind rS1 and were distributed in tissues with various patterns. The colocalization analysis of rS1 and those potential ligands indicated that the distributions of rS1 are highly consistent with those of ACE 2-like substances and oHSP 70. Both ligands are distributed predominantly in the secretory absorptive cells of the digestive diverticula and may serve as the primary ligands to bind rS1. Therefore, oysters are capable of bioaccumulating the SARS-CoV-2 capsid readily by filter-feeding behavior assisted by specific binding ligands, especially in digestive diverticula. IMPORTANCE This is the first article to investigate the SARS-CoV-2 spike protein bioaccumulation pattern and mechanism in Pacific oysters by the histochemical method. Oysters can bioaccumulate SARS-CoV-2 capsid readily by filter-feeding behavior assisted by specific binding ligands. The new possible foodborne transmission route may change the epidemic prevention strategies and reveal some outbreaks that current conventional epidemic transmission routes cannot explain. This original and interdisciplinary paper advances a mechanistic understanding of the bioaccumulation of SARS-CoV-2 in oysters inhabiting contaminated surface water.

One-Stop Extraction and In Situ RT-qPCR for Ultrasensitive Detection of Highly Diluted SARS-CoV-2 in Large-Volume Samples from Aquatic Environments

Surveillance of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in aquatic environments attracted attention due to its considerable impacts on human health and ecology, especially in countries with poor sanitation standards. Based on a strategy of one-stop extraction and in situ amplification, we developed an ultrasensitive method that uses a polyacrylamide derivative-modified filter disc (PAD-FD), in which highly diluted RNA can be efficiently concentrated onto the filter disc and directly used for amplification. A newly designed spin column with a cup-like filter base facilitated the non-contact transfer of the affinity filter disc from the column to a PCR tube. The limit of detection of the PAD-FD coupled with RT-qPCR is 10 copies/mL. Using 32 suspected SARS-CoV-2 samples, we demonstrated that the detection rate of our method (62.5%, 20/32) was triple the rate of the commercial kit (18.8%, 6/32). Using a PAD-FD, 56.3% (18/32) and 40.6% (13/32) of the 10-fold-dilution samples with river and tap water, respectively, were detected. Even when diluted 100-fold, 28.1% (9/32) and 37.5% (12/32) were still detected in river and tap water, respectively. We believe that the PAD-FD method offers an accurate testing tool for monitoring viral RNA in aquatic environments, contributing to the forewarning of the SARS-CoV-2 outbreak and the breaking of the transmission chain.

SARS-CoV-2 whole-proteome sequences from environment as an indicator of community viral distribution, evolution and epidemiological dynamics: A cohort analysis of Austria

Several investigations have been carried out to detect SARS-CoV-2 samples from the environment such as sewage waters and surface swabs. Whole-proteome sequence analysis of 847 SARS-CoV-2 genome sequences collected from the environment in Austria during 2021 and deposited in GISAID indicates that alpha and delta are two dominant variants, coinciding with the human clinical samples with a Pearson correlation coefficient in the range of 0.58 (alpha variant) to 0.82 (delta variant). Both environmental and human samples show that Austrian SARS-CoV-2 alpha variant is found to possess N protein R203K and G204R/P mutations, whereas they are absent in the delta variant. SARS-CoV-2 delta variant is continuously seen in both the environmental and human clinical samples from the month of September 2021 and it spiked in November 2021, which is directly reflected in the increase of the number of SARS-CoV-2 infections and deaths in Austria during November 2021. Thus, the results presented here indicate that the environmental SARS-CoV-2 whole-genome sequences collected from Austria reflect the community viral distribution, evolution and the concomitant epidemiological dynamics. Since SARS-CoV-2 keeps evolving, the results presented here further suggest the need to monitor the environment for the early detection of SARS-CoV-2 variants to take appropriate precautionary measures.

Persistence and occurrence of SARS-CoV-2 in water and wastewater environments: a review of the current literature

As the world continues to cope with the COVID-19 pandemic, emerging evidence indicates that respiratory transmission may not the only pathway in which the virus can be spread. This review paper aims to summarize current knowledge surrounding possible fecal-oral transmission of SARS-CoV-2. It covers recent evidence of proliferation of SARS-CoV-2 in the gastrointestinal tract, as well as presence and persistence of SARS-CoV-2 in water, and suggested future directions. Research indicates that SARS-CoV-2 can actively replicate in the human gastrointestinal system and can subsequently be shed via feces. Several countries have reported SARS-CoV-2 RNA fractions in wastewater systems, and various factors such as temperature and presence of solids have been shown to affect the survival of the virus in water. The detection of RNA does not guarantee infectivity, as current methods such as RT-qPCR are not yet able to distinguish between infectious and non-infectious particles. More research is needed to determine survival time and potential infectivity, as well as to develop more accurate methods for detection and surveillance.

Implementing wastewater surveillance for SARS-CoV-2 on a university campus: Lessons learned

Wastewater surveillance, also known as wastewater-based epidemiology (WBE), has been successfully used to detect SARS-CoV-2 and other viruses in sewage in many locations in the United States and globally. This includes implementation of the surveillance on college and university campuses. A two-phase study was conducted during the 2020-2021 academic year to test the feasibility of a WBE system on campus and to supplement the clinical COVID-19 testing performed for the student, staff, and faculty body. The primary objective during the Fall 2020 semester was to monitor a large portion of the on-campus population and to obtain an understanding of the spreading of the SARS-CoV-2 virus. The Spring 2021 objective was focused on selected residence halls and groups of residents on campus, as this was more efficient and relevant for an effective follow-up response. Logistical problems and planning oversights initially occurred but were corrected with improved communication and experience. Many lessons were learned, including effective mapping, site planning, communication, personnel organization, and equipment management, and obtained along the way, thereby paving an opportune guide for future planning efforts. PRACTITIONER POINTS: WBE was successful in the detection of many SARS-CoV-2 variants incl. Alpha, Beta, Gamma, Delta, Lambda, Mu, and Omicron. Careful planning and contingencies were essential for a successful implementation of a SARS-CoV-2 monitoring program. A surveillance program may be important for detection and monitoring of other public health relevant targets in wastewater incl. bacteria, viruses, fungi and viruses. Diverse lessons were learned incl. effective mapping, site planning, communication, personnel organization, and equipment management, thereby providing a guide for future planning efforts.

Effectiveness of environmental surveillance of SARS-CoV-2 as an early warning system during the first year of the COVID-19 pandemic: a systematic review

Since infected persons shed SARS-CoV-2 in faeces before symptoms appear, environmental surveillance (ES) may serve as an early warning system (EWS) for COVID-19 and new variants of concern. The ES of SARS-CoV-2 has been widely reviewed; however, its effectiveness as an EWS for SARS-CoV-2 in terms of timeliness, sensitivity and specificity has not been systematically assessed. We conducted a systematic review to identify and synthesise evidence on the ES of SARS-CoV-2 as an EWS to evaluate the added value for public health. Of 1,014 studies identified, we considered 29 for a qualitative synthesis of the timeliness of ES as an EWS for COVID-19, while six studies were assessed for the ability to detect new variants and two for both aims. The synthesis indicates ES may serve as an EWS of 1-2 weeks. ES could complement clinical surveillance for SARS-CoV-2; however, its cost-benefit value for public health decisions needs to be assessed based on the stage of the pandemic and resources available. Studies focusing methodological knowledge gaps as well as how to use and interpret ES signals for public health actions are needed, as is the sharing of knowledge within countries/areas with long experience of such surveillance.

The Importance of Behavioral and Native Factors on COVID-19 Infection and Severity: Insights from a Preliminary Cross-Sectional Study

The COVID-19 pandemic has had a major impact on a global scale. Understanding the innate and lifestyle-related factors influencing the rate and severity of COVID-19 is important for making evidence-based recommendations. This cross-sectional study aims at establishing a potential relationship between human characteristics and vulnerability/resistance to SARS-CoV-2. We hypothesize that the impact of the virus is not the same due to cultural and ethnic differences. A cross-sectional study was performed using an online questionnaire. The methodology included the development of a multi-language survey, expert evaluation, and data analysis. Data were collected using a 13-item pre-tested questionnaire based on a literature review between 9 December 2020 and 21 July 2021. Data were statistically analyzed using logistic regression. For a total of 1125 respondents, 332 (29.5%) were COVID-19 positive; among them, 130 (11.5%) required home-based treatment, and 14 (1.2%) intensive care. The significant and most influential factors on infection included age, physical activity, and health status (p < 0.05), i.e., better physical activity and better health status significantly reduced the possibility of infection, while older age significantly increased it. The severity of infection was negatively associated with the acceptance (adherence and respect) of preventive measures and positively associated with tobacco (p < 0.05), i.e., smoking regularly significantly increases the severity of COVID-19 infection. This suggests the importance of behavioral factors compared to innate ones. Apparently, individual behavior is mainly responsible for the spread of the virus. Therefore, adopting a healthy lifestyle and scrupulously observing preventive measures, including vaccination, would greatly limit the probability of infection and prevent the development of severe COVID-19.

Changes in water use and wastewater generation influenced by the COVID-19 pandemic: A case study of China

This paper examines and projects the water use and wastewater generation during and after the SARS-CoV-2 (COVID-19) in China, and discussed the water use/wastewater generation pattern changes among different sectors. Existing studies on the impact of pandemic spread-prevention measures on water consumption and wastewater treatment during the pandemic are reviewed. The water use and wastewater discharge in China through the COVID-19 period are then projected and analyzed using Multivariate Linear Regression. The projection is carried out for years 2019-2023 and covers an (estimated) full process of pre-pandemic, pandemic outbreak, and recovery phase and provides essential information for determining the complete phase impact of the COVID-19. Two scenarios, i.e. the recovery scenario and the business as usual scenario, are set to investigate the water use and wastewater generation characteristics after the pandemic. The results imply that in both scenarios, the water use in China shows a V-shaped trend from 2019 to 2023 and reached a low point in 2020 of 5,813✕10⁸ m³. The wastewater discharge shows an increasing trend throughout the COVID period in both scenarios. The results are also compared with the water consumption and wastewater generation during the SARS-CoV-1 period. The implication for policymakers is the possible increase of water use and wastewater discharge in the post COVID period and the necessity to ensure the water supply and control of water pollution and wastewater discharge.

The Influence of Municipal Wastewater Treatment Technologies on the Biological Stabilization of Sewage Sludge: A Systematic Review

Various wastewater treatment technologies are available today and biological processes are predominantly used in these technologies. Increasing wastewater treatment systems produces large amounts of sewage sludge with variable quantities and qualities, which must be properly managed. Anaerobic and aerobic digestion and composting are major strategies to treat this sludge. The main indicators of biological stabilization are volatile fatty acids (VFAs), volatile solids (VS), the carbon/nitrogen (C/N) ratio, humic substances (HS), the total organic carbon (TOC), the carbon dioxide (CO2) evolution rate, the specific oxygen uptake rate (SOUR), and the Dewar test; however, different criteria exist for the same indicators. Although there is no consensus for defining the stability of sewage sludge (biosolids) in the research and regulations reviewed, controlling the biological degradation, vector attraction, and odor determines the biological stabilization of sewage sludge. Because pollutants and pathogens are not completely removed in biological stabilization processes, further treatments to improve the quality of biosolids and to ensure their safe use should be explored.

Persistence of SARS-CoV-2 RNA in wastewater after the end of the COVID-19 epidemics

Although the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been widely detected in wastewater in many countries to track the COVID-19 pandemic development, it is still a lack of clear understanding of the persistence of SARS-CoV-2 in raw sewage, especially after the end of the COVID-19 pandemic event. To fill this knowledge gap, this study conducted a field trial on the SARS-CoV-2 presence in various wastewater facilities after the end of the COVID-19 epidemics in Beijing. The result showed that the wastewater treatment facility is a large SARS-CoV-2 repository. The viral RNA was still present in hospital sewage for 15 days and was continually detected in municipal WWTPs for more than 19 days after the end of the local COVID-19 epidemics. The T₉₀ values of the SARS-CoV-2 RNA in raw wastewater were 17.17-8.42 days in the wastewater at 4 ℃ and 26 ℃, respectively, meaning that the decay rates of low titer viruses in raw sewage were much faster. The results confirmed that the SARS-CoV-2 RNA could persist in wastewater for more than two weeks, especially at lower temperatures. The sewage systems would be a virus repository and prolong the presence of the residual SARS-CoV-2 RNA. The study could enhance further understanding of the presence of SARS-CoV-2 RNA in raw wastewater.

Coronaviruses and SARS-CoV-2 in sewerage and their removal: Step by step in wastewater treatment plants

The fate of Coronaviruses (CoVs) and in particular SARS-CoV-2 in wastewater treatment plants (WWTPs) has not been completely understood yet, but an adequate knowledge on the removal performances in WWTPs could help to prevent waterborne transmission of the virus that is still under debate. CoVs and SARS-CoV-2 are discharged from faeces into the sewer network and reach WWTPs within a few hours. This review presents the fate of SARS-CoV-2 and other CoVs in the primary, secondary and tertiary treatments of WWTPs as well as in sludge treatments. The viral loads decrease progressively along with the treatments from 20 to 3.0E+06 GU/L (Genomic Units/L) in the influent wastewater to concentrations below 2.50E+05 GU/L after secondary biological treatments and finally to negative concentrations (below detection limit) in disinfected effluents. Reduction of CoVs is due to (i) natural decay under unfavourable conditions (solids, microorganisms, temperature) for relatively long hydraulic retention times and (ii) processes of sedimentation, filtration, predation, adsorption, disinfection. In primary and secondary settling, due to the hydrophobic properties, a partial accumulation of CoVs may occur in the separated sludge. In secondary treatment (i.e. activated sludge) CoVs and SARS-CoV-2 loads can be reduced only by about one logarithm (∼90%). To enhance this removal, tertiary treatment with ultrafiltration (Membrane Bioreactors) and chemical disinfection or UV light is needed. CoVs and SARS-CoV-2 in the sludge (1.2E+04-4.6E+08 GU/L) can be inactivated significantly in the thermophilic digestion (55 °C), while mesophilic temperatures (33-37 °C) are not efficient. Additional studies are required to investigate the infectivity of SARS-CoV-2 in WWTPs, especially in view of increasing interest in wastewater reclamation and reuse.

Current perspective in metal oxide based photocatalysts for virus disinfection: A review

Nanotechnology holds huge potential for the prevention of various viral outbreaks that have increased at a disquieting rate over the past decades. Metal oxide nanomaterials with oxidative capability are the effective materials that provide platforms as well as tools for the well understanding of the mechanism, its detection, and treatment of various viral diseases like measles, influenza, herpes, ebola, current COVID-19 etc. In this inclusive review, we survey various previous research articles on different notable photoactive transition metal oxides that possess enough potential to act as antiviral agents for the deactivation of harmful viruses. We investigated and highlighted the plausible photocatalytic oxidative mechanism of photoactive transition metal oxides in degrading viral coatings, genomic RNA using suitable free radical generation. The key finding of the present review article including the discovery of a vision on the suitable photocatalytic transition metal oxides that have been proven to be excellent against harmful viruses and consequently combatting deadly CoV-2 in the environment. This review intends to provide conclusive remarks and a realistic outlook on other advanced photocatalytic metal oxides as a potential solution in battling other similar upcoming pandemics.

A review of the potential of conventional and advanced membrane technology in the removal of pathogens from wastewater

Consumption of pathogenic contaminated water has claimed the lives of many people. Hence, this scenario has emphasized the urgent need for research methods to avoid, treat and eliminate harmful pathogens in wastewater. Therefore, effective water treatment has become a matter of utmost importance. Membrane technology offers purer, cleaner, and pathogen-free water through the water separation method via a permeable membrane. Advanced membrane technology such as nanocomposite membrane, membrane distillation, membrane bioreactor, and photocatalytic membrane reactor can offer synergistic effects in removing pathogen through the integration of additional functionality and filtration in a single chamber. This paper also comprehensively discussed the application, challenges, and future perspective of the advanced membrane technology as a promising alternative in battling pathogenic microbial contaminants, which will also be beneficial and valuable in managing pandemics in the future as well as protecting human health and the environment. In addition, the potential of membrane technology in battling the ongoing global pandemic of coronavirus disease 2019 (COVID-19) was also discussed briefly.

Nanoparticle Engineered Photocatalytic Paints: A Roadmap to Self-Sterilizing against the Spread of Communicable Diseases

Applications of visible-light photocatalytic engineered nanomaterials in the preparation of smart paints are of recent origin. The authors have revealed a great potential of these new paints for self-sterilizing of the surfaces in hospitals and public places simply with visible light exposure and this is reported for the first time in this review. A recent example of a communicable disease such as COVID-19 is considered. With all precautions and preventions taken as suggested by the World Health Organization (WHO), COVID-19 has remained present for a longer time compared to other diseases. It has affected millions of people worldwide and the significant challenge remains of preventing infections due to SARS-CoV-2. The present review is focused on revealing the cause of this widespread disease and suggests a roadmap to control the spread of disease. It is understood that the transmission of SARS-CoV-2 virus takes place through contact surfaces such as doorknobs, packaging and handrails, which may be responsible for many preventable and nosocomial infections. In addition, due to the potent transmissibility of SARS-CoV-2, its ability to survive for longer periods on common touch surfaces is also an important reason for the spread of COVID-19. The existing antimicrobial cleaning technologies used in hospitals are not suitable, viable or economical to keep public places free from such infections. Hence, in this review, an innovative approach of coating surfaces in public places with visible-light photocatalytic nanocomposite paints has been suggested as a roadmap to self-sterilizing against the spread of communicable diseases. The formulations of different nanoparticle engineered photocatalytic paints with their ability to destroy pathogens using visible light, alongwith the field trials are also summarized and reported in this review. The potential suggestions for controlling the spread of communicable diseases are also listed at the end of the review.

Wastewater, waste, and water-based epidemiology (WWW-BE): A novel hypothesis and decision-support tool to unravel COVID-19 in low-income settings?

Traditional wastewater-based epidemiology (W-BE) relying on SARS-CoV-2 RNA detection in wastewater is attractive for understanding COVID-19. Yet traditional W-BE based on centralized wastewaters excludes putative SARS-CoV-2 reservoirs such as: (i) wastewaters from shared on-site sanitation facilities, (ii) solid waste including faecal sludge from non-flushing on-site sanitation systems, and COVID-19 personal protective equipment (PPE), (iii) raw/untreated water, and (iv) drinking water supply systems in low-income countries (LICs). A novel hypothesis and decision-support tool based on Wastewater (on-site sanitation, municipal sewer systems), solid Waste, and raw/untreated and drinking Water-based epidemiology (WWW-BE) is proposed for understanding COVID-19 in LICs. The WWW-BE conceptual framework, including components and principles is presented. Evidence on the presence of SARS-CoV-2 and its proxies in wastewaters, solid materials/waste (papers, metals, fabric, plastics), and raw/untreated surface water, groundwater and drinking water is discussed. Taken together, wastewaters from municipal sewer and on-site sanitation systems, solid waste such as faecal sludge and COVID-19 PPE, raw/untreated surface water and groundwater, and drinking water systems in LICs act as potential reservoirs that receive and harbour SARS-CoV-2, and then transmit it to humans. Hence, WWW-BE could serve a dual function in estimating the prevalence and potential transmission of COVID-19. Several applications of WWW-BE as a hypothesis and decision support tool in LICs are discussed. WWW-BE aggregates data from various infected persons in a spatial unit, hence, putatively requires less resources (analytical kits, personnel) than individual diagnostic testing, making it an ideal decision-support tool for LICs. The novelty, and a critique of WWW-BE versus traditional W-BE are presented. Potential challenges of WWW-BE include: (i) biohazards and biosafety risks, (ii) lack of expertise, analytical equipment, and accredited laboratories, and (iii) high uncertainties in estimates of COVID-19 cases. Future perspectives and research directions including key knowledge gaps and the application of novel and emerging technologies in WWW-BE are discussed.

Longitudinal, virological, and serological assessment of hospitalized COVID-19 patients

Here we described the virological and serological assessment of 23 COVID-19 patients hospitalized and followed up in Milan, Italy, during the first wave of COVID-19 pandemic. Nasopharyngeal (NPS), anal swabs, and blood samples were collected from 23 COVID-19 patients, at hospital admission, and periodically up to discharge, for a median time of 20 days (3-83 days). RNA was isolated and tested for SARS-CoV-2 by qRT-PCR; anti-SARS-CoV-2 IgM and IgG antibody titers were evaluated in serum samples by ELISA. SARS-CoV-2 genome was detected in the NPS swabs of the 23 patients, at the admission, and 8/19 (42.1%) were still positive at the discharge. Anal swabs were positive to SARS-CoV-2 RNA detection in 20/23 (86.9%) patients; 6/19 (31.6%) were still positive at discharge. The mean time of RNA negative conversion was 17 days (4-36 days) and 33 days (4-77 days), for NPS and anal swabs, respectively. SARS-CoV-2-RNA was detected in the blood of 6/23 (26.1%) patients. Thirteen/23 (56.5%) and 17/23 (73.9%) patients were seropositive for IgM and IgG, respectively, at the admission, and the median IgM and IgG levels significantly (p < 0.05) increased after 13 days. Although the limited cohort size, our report provides evidence that SARS-CoV-2 is shed through multiple routes, with important implications in healthcare settings.

Monitoring COVID-19 through SARS-CoV-2 quantification in wastewater: progress, challenges and prospects

Wastewater‐Based Epidemiology (WBE) is widely used to monitor the progression of the current SARS‐CoV‐2 pandemic at local levels. In this review, we address the different approaches to the steps needed for this surveillance: sampling wastewaters (WWs), concentrating the virus from the samples and quantifying them by qPCR, focusing on the main limitations of the methodologies used. Factors that can influence SARS‐CoV‐2 monitoring in WWs include: (i) physical parameters as temperature that can hamper the detection in warm seasons and tropical regions, (ii) sampling methodologies and timetables, being composite samples and Moore swabs the less variable and more sensitive approaches, (iii) virus concentration methodologies that need to be feasible and practicable in simpler laboratories and (iv) detection methodologies that should tend to use faster and cost‐effective procedures. The efficiency of WW treatments and the use of WWs for SARS‐CoV‐2 variants detection are also addressed. Furthermore, we discuss the need for the development of common standardized protocols, although these must be versatile enough to comprise variations among target communities. WBE screening of risk populations will allow for the prediction of future outbreaks, thus alerting authorities to implement early action measurements.

SARS-CoV-2 at the human-animal interphase: A review

Since its emergence in China in December 2019, COVID-19 remains the recent leading disease of concern drawing the public health attention globally. The disease is known of viral origin and zoonotic nature originating from animals. However, to date neither the source of the spillover nor the intermediate hosts are identified. Moreover, the public health situation is intermittently aggravated by identification of new animals susceptible to the SARS-CoV-2 infection, potentially replicating the virus and maintaining intra and interspecies spread of the disease. Although the role of a given animal and/or its produce is important to map the disease pattern, continuous efforts should be undertaken to further understand the epidemiology of SARS-CoV-2, a vital step to establish effective disease prevention and control strategy. This manuscript attempted to review updates regarding SARS-CoV-2 infection at the human-animal interface with consideration to postulations on the genetic relatedness and origin of the different SARS-CoV-2 variants isolated from different animal species. Also, the review addresses the possible role of different animal species and their produce in transmission of the disease. Also, the manuscript discussed the contamination potentiality of the virus and its environmental stability. Finally, we reviewed the currently instituted measures to prevent and manage the spread of SARS-CoV-2 infection. The manuscript suggested the One Health based control measures that could prove of value for the near future.

SARS-CoV-2 detection in wastewater using multiplex quantitative PCR

A multiplex reverse transcription quantitative PCR (RT-qPCR)-based method was designed for the simultaneous detection of different SARS-CoV-2 genes. In this study, we used three target genes encoding for the nucleocapsid 1 and 3 (N1, N3), and the spike (S) proteins, all commonly used in the detection of SARS-CoV-2 in human and environmental samples. The performance of the multiplex assay, compared to the single assay was assessed for the standard calibration curve, required for absolute quantification, and then, for the real environmental samples to detect SARS-CoV-2. For this latter, four environmental samples were collected at a local wastewater treatment plant (WWTP). The results showed that the cycle threshold (Ct) values of the multiplex were comparable to the values obtained by the singleplex PCR. The amplification of the three target genes indicated the presence of SARS-CoV-2 in the four water samples with an increasing trend in February and these results were confirmed in the multiplex approach, showing the robustness of this method and its applicability for the relative abundance analysis among the samples. Overall, both the laboratory and field work results demonstrated that the multiplex PCR assay developed in this study could provide a method for SARS-CoV-2 detection as robust as the single qPCR, but faster and cost-effective, reducing by three times the number of reactions, and consequently the handling time and reagents.

Assessing the impact of non-pharmaceutical interventions (NPI) on the dynamics of COVID-19: A mathematical modelling study of the case of Ethiopia

The World Health Organization (WHO) declared COVID-19 a pandemic on March 11, 2020 and by November 14, 2020 there were 53.3M confirmed cases and 1.3M reported deaths in the world. In the same period, Ethiopia reported 102K cases and 1.5K deaths. Effective public health preparedness and response to COVID-19 requires timely projections of the time and size of the peak of the outbreak. Currently, Ethiopia under the COVAX facility has begun vaccinating high risk populations but due to vaccine supply shortages and the absence of an effective treatment, the implementation of NPIs (non-pharmaceutical interventions), like hand washing, wearing face coverings or social distancing, still remain the most effective methods of controlling the pandemic as recommended by WHO. This study proposes a modified Susceptible Exposed Infected and Recovered (SEIR) model to predict the number of COVID-19 cases at different stages of the disease under the implementation of NPIs at different adherence levels in both urban and rural settings of Ethiopia. To estimate the number of cases and their peak time, 30 different scenarios were simulated. The results indicated that the peak time of the pandemic is different in urban and rural populations of Ethiopia. In the urban population, under moderate implementation of three NPIs the pandemic will be expected to reach its peak in December, 2020 with 147,972 cases, of which 18,100 are symptomatic and 957 will require admission to an Intensive Care Unit (ICU). Among the implemented NPIs, increasing the coverage of wearing masks by 10% could reduce the number of new cases on average by one-fifth in urban-populations. Varying the coverage of wearing masks in rural populations minimally reduces the number of cases. In conclusion, the models indicate that the projected number of hospital cases during the peak time is higher than the Ethiopian health system capacity. To contain symptomatic and ICU cases within the health system capacity, the government should pay attention to the strict implementation of the existing NPIs or impose additional public health measures.

Wastewater aerosols produced during flushing toilets, WWTPs, and irrigation with reclaimed municipal wastewater as indirect exposure to SARS-CoV-2

The detection of SARS-CoV-2 RNA in raw and treated wastewater can open up a fresh perspective to waterborne and aerosolized wastewater as a new transmission route of SARS-CoV-2 RNA during the current pandemic. The aim of this paper is to discuss the potential transmission of SARS-CoV-2 RNA from wastewater aerosols formed during toilet flushing, plumbing failure, wastewater treatment plants, and municipal wastewater reuse for irrigation. Moreover, how these aerosols might increase the risk of exposure to this novel coronavirus (SARS-CoV-2 RNA). This article supplies a review of the literature on the presence of SARS-CoV-2 RNA in untreated wastewater, as well as the fate and stability of SARS-CoV-2 RNA in wastewater. We also reviewed the existing literatures on generation and transmission of aerosolized wastewater through flush a toilet, house's plumbing networks, WWTPs, wastewater reuse for irrigation of agricultural areas. Finally, the article briefly studies the potential risk of infection with exposure to the fecal bioaerosols of SARS-CoV-2 RNA for the people who might be exposed through flushing toilets or faulty building plumbing systems, operators/workers in wastewater treatment plants, and workers of fields irrigated with treated wastewater - based on current knowledge. Although this review highlights the indirect transmission of SARS-CoV-2 RNA through wastewater aerosols, no research has yet clearly demonstrated the role of aerosolized wastewater in disease transmission regarding the continuation of this pandemic. Therefore, there is a need for additional studies on wastewater aerosols in transmission of COVID-19.

The COVID-19 pandemic and its implications on the environment

The emerging threat posed by COVID-19 pandemic has strongly modified our lifestyle, making urgent to re-consider the humans-environment relationships and stimulating towards more sustainable choices in our daily behavior. Scientific evidences showed that the onset of new viral pathogens with a high epidemic-pandemic potential is often the result of complex interactions between animals, humans and environment. In this context, the interest of the scientific community has also been attracted towards the potential interactions of SARS-CoV-2 with environmental compartments. Many issues, ranging from the epidemiology and persistence of SARS-CoV-2 in water bodies to the potential implications of lockdown measures on environmental quality status are here reviewed, with a special reference to marine ecosystems. Due to current sanitary emergence, the relevance of pilot studies regarding the interactions between SARS-CoV-2 spread and the direct and indirect environmental impacts of the COVID-19 pandemic, that are still a matter of scientific debate, is underlined.

Reliability of thermal desalination (solar stills) for water/wastewater treatment in light of COVID-19 (novel coronavirus "SARS-CoV-2") pandemic: What should consider?

The COVID-19 pandemic disturbed the world from the beginning of 2020. The high excessive number of patients and the presence of the SARS-CoV-2 in human excreta and urine even after the infected person's respiratory tests were negative, results in a heavy load of viral in various water bodies and mostly untreated wastewaters. In the present study, the reliability of using small-scale solar thermal desalination systems (solar stills) during a situation like the COVID-19 pandemic is discussed. Pollution of water bodies through the SARS-CoV-2 via numerous routes increases the risk of contaminating the feed water and subsequently the whole structure of solar stills. Since the transmission of pathogens (particle size: 0.5-3 μm) via droplets of water in solar still is reported before, transmitting of SARS-CoV-2 via droplets of water which multiple times smaller (particle size: 60-140 nm) than those pathogens is a concern. The most important issue which must be highlighted is that solar stills worked at low-temperature while the viability and survival of the SARS-CoV-2 in various water matrices in the temperature range (4-37 °C) for several days is reported. In this regard, using solar stills during the COVID-19 pandemic need further consideration by all researchers and people around the world.

Factors influencing recovery of SARS-CoV-2 RNA in raw sewage and wastewater sludge using polyethylene glycol-based concentration method

Wastewater surveillance for monitoring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important epidemiologic tool for the assessment of population-wide coronavirus disease 2019 (COVID-19). This tool can be successfully implemented only if SARS-CoV-2 RNA in wastewater can be accurately recovered and quantified. The lack of standardized procedure for wastewater virus analysis has resulted in varying SARS-CoV-2 concentrations for the same sample. This study reports the effect of 4 key factors-sample volume, percentage polyethylene glycol (PEG)-NaCl, incubation period, and storage duration at 4°C-on the recovery of spiked noninfectious SARS-CoV-2 RNA in raw sewage and sludge samples. N1 and N2 genes of SARS-CoV-2 were quantified using the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and digital droplet PCR (RT-ddPCR) techniques. Results indicate that 1) for raw sewage, 50-ml sample volume, 30% PEG-NaCl addition, 6-h incubation, and sample analysis within 24 h of collection can result in much better RNA recovery (RT-qPCR: 72% for N1 and 82% for N2; RT-ddPCR: 55% for N1 and 85% for N2) when compared with commonly used PEG-based method; 2) for sludge, the sample analysis using raw sewage protocol and all other variations of each factor mostly resulted in false negatives for both N1 and N2. The absence of N1 and N2 suggests that sludge samples probably need a pretreatment step that releases RNA entrapped in sludge solids back into bulk solution. In conclusion, our modified PEG-based concentration method can cut down the analysis time at least by half, which in turn helps to implement early detection system for SARS-CoV-2 in wastewater.

Decay of infectious SARS-CoV-2 and surrogates in aquatic environments

The introduction of SARS-CoV-2 containing human stool and sewage into water bodies may raise public health concerns. However, assessment of public health risks by faecally contaminated water is limited by a lack of knowledge regarding the persistence of infectious SARS-CoV-2 in water. In the present study the decay rates of viable infectious SARS-CoV-2 and SARS-CoV-2 RNA were determined in river and seawater at 4 and 20°C. These decay rates were compared to S. typhimurium bacteriophage MS2 and pepper mild mottle virus (PMMoV). Persistence of viable SARS-CoV-2 was temperature dependent, remaining infectious for significantly longer periods of time in both freshwater and seawater at 4°C than at 20°C. T₉₀ for infectious SARS-CoV-2 in river water was 2.3 days and 3.8 days at 20°C and 4°C, respectively. The T₉₀ values were 1.1 days and 2.2 days in seawater at 20°C and 4°C, respectively. In contrast to the rapid inactivation of infectious SARS-CoV-2 in river and sea water, viral RNA was relatively stable. The RNA decay rates were increased in non-sterilised river and seawater, presumably due to the presence of microbiota. The decay rates of infectious MS2, MS2 RNA and PMMoV RNA differed significantly from the decay rate of SARS-CoV-2 RNA, suggesting that their use as surrogate markers for the persistence of SARS-CoV-2 in the environment is limited.

A review on the potential of photocatalysis in combatting SARS-CoV-2 in wastewater

Photocatalytic technology offers powerful virus disinfection in wastewater via oxidative capability with minimum harmful by-products generation. This review paper aims to provide state-of-the-art photocatalytic technology in battling transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater. Prior to that, the advantages and limitations of the existing conventional and advanced oxidation processes for virus disinfection in water systems were thoroughly examined. A wide spectrum of virus degradation by various photocatalysts was then considered to understand the potential mechanism for deactivating this deadly virus. The challenges and future perspectives were comprehensively discussed at the end of this review describing the limitations of current photocatalytic technology and suggesting a realistic outlook on advanced photocatalytic technology as a potential solution in dealing with similar upcoming pandemics. The major finding of this review including discovery of a vision on the possible photocatalytic approaches that have been proven to be outstanding against other viruses and subsequently combatting SARS-CoV-2 in wastewater. This review intends to deliver insightful information and discussion on the potential of photocatalysis in battling COVID-19 transmission through wastewater.

SARS-CoV-2 and other viruses in soil: An environmental outlook

In the present review, the authors shed light on the SARS-CoV-2 impact, persistence, and monitoring in the soil environment. With this purpose, several aspects have been deepened: i) viruses in soil ecosystems; ii) direct and indirect impact on the soil before and after the pandemic, and iii) methods for quantification of viruses and SARS-CoV-2 monitoring in soil. Viruses are present in soil (i.e. up to 417 × 10⁷ viruses per g TS^-1 in wetlands) and can affect the behavior and ecology of other life forms (e.g. bacteria), which are remarkably important for maintaining environmental equilibrium. Also, SARS-CoV-2 can be found in soil (i.e. up to 550 copies·g^-1). Considering that the SARS-CoV-2 is very recent, poor knowledge is available in the literature on persistence in the soil and reference has been made to coronaviruses and other families of viruses. For instance, the survival of enveloped viruses (e.g. SARS-CoV) can reach 90 days in soils with 10% of moisture content at ambient. In such a context, the possible spread of the SARS-CoV-2 in the soil was evaluated by analyzing the possible contamination routes.

Assessing and managing SARS-CoV-2 occupational health risk to workers handling residuals and biosolids

Current wastewater worker guidance from the United States Environmental Protection Agency (USEPA) aligns with the Centers for Disease Control and Prevention (CDC) and the Occupational Safety and Health Administration (OSHA) recommendations and states that no additional specific protections against SARS-CoV-2, the virus that causes COVID-19 infections, are recommended for employees involved in wastewater management operations with residuals, sludge, and biosolids at water resource recovery facilities. The USEPA guidance references a document from 2002 that summarizes practices required for protection of workers handling class B biosolids to minimize exposure to pathogens including viruses. While there is no documented evidence that residuals or biosolids of any treatment level contain infectious SARS-CoV-2 or are a source of transmission of this current pandemic strain of coronavirus, this review summarizes and examines whether the provided federal guidance is sufficient to protect workers in view of currently available data on SARS-CoV-2 persistence and transmission. No currently available epidemiological data establishes a direct link between wastewater sludge or biosolids and risk of infection from the SARS-CoV-2. Despite shedding of the RNA of the virus in feces, there is no evidence supporting the presence or transmission of infectious SARS-CoV-2 through the wastewater system or in biosolids. In addition, this review presents previous epidemiologic data related to other non-enveloped viruses. Overall, the risk for exposure to SARS-CoV-2, or any pathogen, decreases with increasing treatment measures. As a result, the highest risk of exposure is related to spreading and handling untreated feces or stool, followed by untreated municipal sludge, the class B biosolids, while lowest risk is associated with spreading or handling Class A biosolids. This review reinforces federal recommendations and the importance of vigilance in applying occupational risk mitigation measures to protect public and occupational health.

COVID-19 and future pandemics: a global systems approach and relevance to SDGs

Background

The COVID-19 pandemic is adversely impacting modern human civilization. A global view using a systems science approach is necessary to recognize the close interactions between health of animals, humans and the environment.

Discussion

A model is developed initially by describing five sequential or parallel steps on how a RNA virus emerged from animals and became a pandemic: 1. Origins in the animal kingdom; 2. Transmission to domesticated animals; 3. Inter-species transmission to humans; 4. Local epidemics; 5. Global spread towards a pandemic. The next stage identifies global level determinants from the physical environments, the biosphere and social environment that influence these steps to derive a generic conceptual model. It identifies that future pandemics are likely to emerge from ecological processes (climate change, loss of biodiversity), anthropogenic social processes (i.e. corporate interests, culture and globalization) and world population growth. Intervention would therefore require modifications or dampening these generators and prevent future periodic pandemics that would reverse human development.

Addressing issues such as poorly planned urbanization, climate change and deforestation coincide with SDGs such as sustainable cities and communities (Goal 11), climate action (Goal 13) and preserving forests and other ecosystems (Goal 15). This will be an added justification to address them as global priorities. Some determinants in the model are poorly addressed by SDGs such as the case of population pressures, cultural factors, corporate interests and globalization. The overarching process of globalization will require modifications to the structures, processes and mechanisms of global governance. The defects in global governance are arguably due to historical reasons and the neo-liberal capitalist order. This became evident especially in the aftermath of the COVID-19 when the vaccination roll-out led to violations of universal values of equity and right to life by some of the powerful and affluent nations.

Summary

A systems approach leads us to a model that shows the need to tackle several factors, some of which are not adequately addressed by SDGs and require restructuring of global governance and political economy.

Risk assessment of SARS-CoV-2 infection in free-ranging wild animals in Belgium

The aim of this review paper is to evaluate the putative susceptibilities of different free-ranging wild animal species in Belgium to SARS-CoV-2 and provide a risk assessment of SARS-CoV-2 infection in those animals. Since the onset of the COVID-19 pandemic, natural SARS-CoV-2 infections have mainly been confirmed in domestic and production animals, and in wild animals kept in captivity, although the numbers remain limited when compared to human cases. Recently, the first SARS-CoV-2 infections in presumably escaped minks found in the wild have been detected, further addressing the much-feared scenario of transmission of the virus to animals living in the wild and its consequences. Considering the most likely origin of the virus being a wild animal and the putative susceptibilities of free-ranging wild animal species to SARS-CoV-2, the risk of infection with possible establishment of the virus in these populations has to be investigated closely. The authors conclude that most attention should be given to surveillance and awareness-raising activities for SARS-CoV-2 infection in wild mustelids, bats, wild canids and felids, particularly these collected in wildlife rescue centres. People involved in frequent and close contact with wild animals should take all necessary precautionary measures to protect wild animals against exposure to the virus. More than one year after the first detection of SARS-CoV-2 in humans, the time has come to increase investments in research and surveillance activities in animals, including in free-ranging wild animals, as part of a One Health control of this pandemic. This study focussing on Belgium could be helpful for other countries with similar animal densities and ecosystems.

Potential antiviral activity of isorhamnetin against SARS-CoV-2 spike pseudotyped virus in vitro

Coronavirus Disease 2019 (COVID-19) cases and deaths are still rising worldwide, there is currently no effective treatment for severe inflammation and acute lung injury caused by new coronavirus (SARS-COV-2) infection. Therapies to prevent or treat COVID-19, including antiviral drug and several vaccines, are still being development. Human angiotensin-converting enzyme 2 (ACE2), expressing in lung, has been confirmed to be a receptor for SARS-COV-2 infection, interventions for attachment of spike protein of SARS-CoV-2 to ACE2 may be a potential approach to prevent viral infections and it is considered as a potential target for drug development. In this study, we observed that seabuckthorn and its flavonoid compounds quercetin and isorhamnetin were shown strong retention to ACE2 overexpression HEK293 (ACE2^h ) cells by CMC analysis. Based on drug receptor interaction analysis and viral entry studies in vitro, we evaluated the interaction of two flavonoid compounds and ACE2 as well as the inhibitory effect of the two compounds on viral entry. Surface plasmon resonance assay proved the effect that isorhamnetin bound to the ACE2, and its affinity (KD value) was at the micromolar level, that was, 2.51 ± 0.68 μM. Viral entry studies in vitro indicated that isorhamnetin inhibited SARS-CoV-2 spike pseudotyped virus entering ACE2^h cells. Based on promising in vitro results, we proposed isorhamnetin to be a potential therapeutic candidate compound against COVID-19.

Evaluation of Two Methods to Concentrate SARS-CoV-2 from Untreated Wastewater

Use of wastewater-based epidemiology as a tool to record and manage the course of SARS-CoV-2 infections in human populations requires information about the efficiency of methods to concentrate the virus from wastewater. In the present study, we spiked untreated wastewater with quantified SARS-CoV-2 positive clinical material and enriched the virus by polyethylene glycol precipitation and ultrafiltration with Vivaspin 10 kDa MWCO columns. SARS-CoV-2 was detected and quantified by reverse transcription quantitative PCR (E- and S-gene) and droplet digital PCR. The concentration of virus with precipitation resulted in mean recoveries between 59.4% and 63.7% whereas rates from 33.0% to 42.6% after ultrafiltration of samples were demonstrated. The results suggest that the use of both methods allows an effective and practicable enrichment of SARS-CoV-2 from raw wastewater.

Indoor versus outdoor transmission of SARS-COV-2: environmental factors in virus spread and underestimated sources of risk

The first case of Coronavirus Disease 2019 (COVID-19), which is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), in Europe was officially confirmed in February 2020. On 11 March 2020, after thousands of deaths from this disease had been reported worldwide, the WHO changed their classification of COVID-19 from a public health emergency of international concern to a pandemic. The SARS-CoV-2 virus has been shown to be much more resistant to environmental degradation than other coated viruses. Several studies have shown that environmental conditions can influence its viability and infectivity. This review summarizes current knowledge on the transmission pathways of the novel coronavirus, and directs attention towards potentially underestimated factors that affect its propagation, notably indoor spread and outdoor risk sources. The contributions of significant indoor factors such as ventilation systems to the spread of this virus need to be carefully ascertained. Outdoor risk sources such as aerosolized particles emitted during wastewater treatment and particulate matter (PM), both of which may act as virus carriers, should be examined as well. This study shows the influence of certain underestimated factors on the environmental behavior and survival of the SARS-CoV-2 virus. These aspects of coronavirus propagation need to be accounted for when devising actions to limit not only the current pandemic but also future outbreaks.

Trend of pneumonia diagnosis in emergency departments as a COVID-19 surveillance system: a time series study

OBJECTIVE

In Italy, the first diagnosis of COVID-19 was confirmed on 20 February 2020 in the Lombardy region. Given the rapid spread of the infection in the population, it was suggested that in Europe, and specifically in Italy, the virus had already been present in the last months of 2019. In this paper, we aim to evaluate the hypothesis on the early presence of the virus in Italy by analysing data on trends of access to emergency departments (EDs) of subjects with a diagnosis of pneumonia during the 2015-2020 period.

DESIGN

Time series cohort study.

SETTING

We collected data on visits due to pneumonia between 1 October 2015 and 31 May 2020 in all EDs of the Agency for Health Protection of Milan (ATS of Milan). Trend in the winter of 2019-2020 was compared with those in the previous 4 years in order to identify unexpected signals potentially associated with the occurrence of the pandemic. Aggregated data were analysed using a Poisson regression model adjusted for seasonality and influenza outbreaks. PRIMARY OUTCOME MEASURES : Daily pneumonia-related visits in EDs. RESULTS : In the studied period, we observed 105 651 pneumonia-related ED visits. Compared with the expected, a lower occurrence was observed in January 2020, while an excess of pneumonia visits started in the province of Lodi on 21 February 2020, and almost 10 days later was observed in the remaining territory of the ATS of Milan. Overall, the peak in excess was found on 17 March 2020 (369 excess visits compared with previous years, 95% CI 353 to 383) and ended in May 2020, the administrative end of the Italian lockdown. CONCLUSIONS : An early warning system based on routinely collected administrative data could be a feasible and low-cost strategy to monitor the actual situation of the virus spread both at local and national levels.