A chronicle of SARS-CoV-2: Seasonality, environmental fate, transport, inactivation, and antiviral drug resistance.

In this review, we present the environmental perspectives of the viruses and antiviral drugs related to SARS-CoV-2. The present review paper discusses occurrence, fate, transport, susceptibility, and inactivation mechanisms of viruses in the environment as well as environmental occurrence and fate of antiviral drugs, and prospects (prevalence and occurrence) of antiviral drug resistance (both antiviral drug resistant viruses and antiviral resistance in the human). During winter, the number of viral disease cases and environmental occurrence of antiviral drug surge due to various biotic and abiotic factors such as transmission pathways, human behaviour, susceptibility, and immunity as well as cold climatic conditions. Adsorption and persistence critically determine the fate and transport of viruses in the environment. Inactivation and disinfection of virus include UV, alcohol, and other chemical-base methods but the susceptibility of virus against these methods varies. Wastewater treatment plants (WWTPs) are major reserviors of antiviral drugs and their metabolites and transformation products. Ecotoxicity of antiviral drug residues against aquatic organisms have been reported, however more threatening is the development of antiviral resistance, both in humans and in wild animal reservoirs. In particular, emergence of antiviral drug-resistant viruses via exposure of wild animals to high loads of antiviral residues during the current pandemic needs further evaluation.

Frontier review on the propensity and repercussion of SARS-CoV-2 migration to aquatic environment.

Increased concern has recently emerged pertaining to the occurrence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in aquatic environment during the current coronavirus disease 2019 (COVID-19) pandemic. While infectious SARS-CoV-2 has yet to be identified in the aquatic environment, the virus potentially enters the wastewater stream from patient excretions and a precautionary approach dictates evaluating transmission pathways to ensure public health and safety. Although enveloped viruses have presumed low persistence in water and are generally susceptible to inactivation by environmental stressors, previously identified enveloped viruses persist in the aqueous environment from days to several weeks. Our analysis suggests that not only the surface water, but also groundwater, represent SARS-CoV-2 control points through possible leaching and infiltrations of effluents from health care facilities, sewage, and drainage water. Most fecally transmitted viruses are highly persistent in the aquatic environment, and therefore, the persistence of SARS-CoV-2 in water is essential to inform its fate in water, wastewater and groundwater and subsequent human exposure.

Monsoon dilutes the concurrence but increases the correlation of viruses and Pharmaceuticals and Personal Care Products (PPCPs) in the urban waters of Guwahati, India: The context of pandemic viruses.

Concurrence of pharmaceuticals and personal care products (PPCPs), pathogenic viruses, metals and microbial pollution along with their seasonal variations in the water environment are overarching in the context of existing pandemic, especially for tropical countries. The present study focuses on the seasonal influence on the vulnerability of urban water in Guwahati, the largest city in North-eastern India, through examining the concurrence of seven PPCPs, five viruses, faecal bacteria and nine metals in surface waters during monsoon (Summer-July 2017) and pre-monsoon (Winter-March 2018). Surface water sampling was carried out at different locations of the Brahmaputra River, its tributary Bharalu River (an unlined urban drain), and Dipor Bill Lake (Ramsar-recognized wetland). Both PPCPs and viruses were at high concentrations (e.g. up to 970 ng L-1 caffeine, 2.5 × 103 copies mL-1 pepper mild mottle virus (PMMoV)) at the confluence points of urban drains and the river, while they were mostly undetectable at both upstream and downstream locations, implying strong self-purification ability of the river. All the analysed PPCPs and viruses were at much higher concentrations during pre-monsoon i.e., winter than during monsoon, implying heavy dilution and temperature effect during the monsoon. Overall, PPCPs and viruses were more correlated in monsoon but the risk quotient in the urban tributary was higher in pre-monsoon (e.g. 5061 in pre-monsoon and 1515 in monsoon for caffeine). PMMoV was found to be an excellent faecal pollution indicator due to its prevalence, detectability and specificity in all seasons. Overall, the seasonal fluctuations of the non-enveloped viruses monitored in this study is likely to be relevant for SARS-CoV-2. We contribute to address the literature scarcity pertaining to seasonal variations in the prevalence of viruses and their concurrences with contaminants of emerging concern.

Making Waves Perspectives of Modelling and Monitoring of SARS-CoV-2 in Aquatic Environment for COVID-19 Pandemic.

Prevalence of SARS-CoV-2 in the aquatic environment pertaining to the COVID-19 pandemic has been a global concern. Though SARS-CoV-2 is known as a respiratory virus, its detection in faecal matter and wastewater demonstrates its enteric involvement resulting in vulnerable aquatic environment. Here, we provide the latest updates on wastewater-based epidemiology, which is gaining interest in the current situation as a unique tool of surveillance and monitoring of the disease. Transport pathways with its migration through wastewater to surface and subsurface waters, probability of infectivity and ways of inactivation of SARS-CoV-2 are discussed in detail. Epidemiological models, especially compartmental projections, have been explained with an emphasis on its limitation and the assumptions on which the future predictions of disease propagation are based. Besides, this review covers various predictive models to track and project disease spread in the future and gives an insight into the probability of a future outbreak of the disease.

First comparison of conventional activated sludge versus root-zone treatment for SARS-CoV-2 RNA removal from wastewaters: Statistical and temporal significance.

In the initial pandemic phase, effluents from wastewater treatment facilities were reported mostly free from Severe Acute Respiratory Coronavirus 2 (SARS-CoV-2) RNA, and thus conventional wastewater treatments were generally considered effective. However, there is a lack of first-hand data on i) comparative efficacy of various treatment processes for SARS-CoV-2 RNA removal; and ii) temporal variations in the removal efficacy of a given treatment process in the backdrop of active COVID-19 cases. This work provides a comparative account of the removal efficacy of conventional activated sludge (CAS) and root zone treatments (RZT) based on weekly wastewater surveillance data, consisting of forty-four samples, during a two-month period. The average genome concentration was higher in the inlets of CAS-based wastewater treatment plant (WWTP) in the Sargasan ward (1.25 × 103 copies/ L), than that of RZT-based WWTP (7.07 × 102 copies/ L) in an academic institution campus of Gandhinagar, Gujarat, India. ORF 1ab and S genes appeared to be more sensitive to treatment i.e., significantly reduced (p < 0.05) than N genes (p > 0.05). CAS treatment exhibited better RNA removal efficacy (p = 0.014) than RZT (p = 0.032). Multivariate analyses suggested that the effective genome concentration should be calculated based on the presence/absence of multiple genes. The present study stresses that treated effluents are not always free from SARS-CoV-2 RNA, and the removal efficacy of a given WWTP is prone to exhibit temporal variability owing to variations in active COVID-19 cases in the vicinity and genetic material accumulation over the time. Disinfection seems less effective than the adsorption and coagulation processes for SARS-CoV-2 removal. Results stress the need for further research on mechanistic insight on SARS-CoV-2 removal through various treatment processes taking solid-liquid partitioning into account.

Antidrug resistance in the Indian ambient waters of Ahmedabad during the COVID-19 pandemic.

The ongoing COVID-19 pandemic increases the consumption of antimicrobial substances (ABS) due to the unavailability of approved vaccine(s). To assess the effect of imprudent consumption of ABS during the COVID-19 pandemic, we compare the 2020 prevalence of antidrug resistance (ADR) of Escherichia coli (E. coli) with a similar survey carried out in 2018 in Ahmedabad, India using SARS-CoV-2 gene detection as a marker of ABS usage. We found a significant ADR increase in 2020 compared to 2018 in ambient water bodies, harbouring a higher incidence of ADR E.coli towards non-fluoroquinolone drugs. Effective SARS-CoV-2 genome copies were found to be associated with the ADR prevalence. The prevalence of ADR depends on the efficiency of WWTPs (Wastewater Treatment Plants) and the catchment area in its vicinity. In the year 2018 study, prevalence of ADR was discretely distributed, and the maximum ADR prevalence recorded was ~60%; against the current homogenous ADR increase, and up to 85% of maximum ADR among the incubated E.coli isolated from the river (Sabarmati) and lake (Chandola and Kankaria) samples. Furthermore, wastewater treatment plants showed less increase in comparison to the ambient waters, which eventually imply that although SARS-CoV-2 genes and faecal pollution may be diluted in the ambient waters, as indicated by low Ct-value and E.coli count, the danger of related aftermath like ADR increase cannot be nullified. Also, Non-fluoroquinolone drugs exhibited overall more resistance than quinolone drugs. Overall, this is probably the first-ever study that traces the COVID-19 pandemic imprints on the prevalence of antidrug resistance (ADR) through wastewater surveillance and hints at monitoring escalation of other environmental health parameters. This study will make the public and policyholders concerned about the optimum use of antibiotics during any kind of treatment.

Predicted occurrence, ecotoxicological risk and environmentally acquired resistance of antiviral drugs associated with COVID-19 in environmental waters.

Antiviral drugs have been used to treat the ever-growing number of coronavirus disease, 2019 (COVID-19) patients. Consequently, unprecedented amounts of such drug residues discharging into ambient waters raise concerns on the potential ecotoxicological effects to aquatic lives, as well as development of antiviral drug-resistance in wildlife. Here, we estimated the occurrence, fate and ecotoxicological risk of 11 therapeutic agents suggested as drugs for COVID-19 treatment and their 13 metabolites in wastewater and environmental waters, based on drug consumption, physical-chemical property, and ecotoxicological and pharmacological data for the drugs, with the aid of quantitative structure-activity relationship (QSAR) modelling. Our results suggest that the removal efficiencies at conventional wastewater treatment plants will remain low (<20%) for half of the substances, and consequently, high drug residues (e.g. 7402 ng/L ribavirin, 4231 ng/L favipiravir, 730 ng/L lopinavir, 319 ng/L remdesivir; each combined for both unchanged forms and metabolites; and when each drug is administered to 100 patients out of 100,000 populations on a day) can be present in secondary effluents and persist in the environmental waters. Ecotoxicological risk in receiving river waters can be high (risk quotient >1) by a use of favipiravir, lopinavir, umifenovir and ritonavir, and medium (risk quotient >0.1) by a use of chloroquine, hydroxychloroquine, remdesivir, and ribavirin, while the risk will remain low (risk quotient <0.1) for dexamethasone and oseltamivir. The potential of wild animals acquiring antiviral drug resistance was estimated to be low. Our prediction suggests a pressing need for proper usage and waste management of antiviral drugs as well as for improving removal efficiencies of drug residues in wastewater.

Potential discharge, attenuation and exposure risk of SARS-CoV-2 in natural water bodies receiving treated wastewater

Recently reported detection of SARS-CoV-2 in wastewater around the world has led to emerging concerns on potential risk in water bodies receiving treated wastewater effluent. This review aims to provide an up-to-date state of key knowledge on the impact of SARS-CoV-2 in natural water bodies receiving treated wastewater. In this review, SARS-CoV-2 concentrations in wastewater, expected removal in WWTPs, and possible dilution and decay in water bodies are reviewed based on past studies on SARS-CoV-2 and related enveloped viruses. We suggest a quantitative microbial risk assessment (QMRA) framework to estimate the potential risk of SARS-CoV-2 in natural water bodies through various water activities. Dose–response model of SARS-CoV and Poisson’s distribution is employed to estimate possible viral ingestion and the annual chance of infection through several water activities in natural water bodies. Finally, future perspectives and research needs have been addressed to overcome the limitations and uncertainty in the risk assessment of SARS-CoV-2 in natural water bodies.

Decay of SARS-CoV-2 RNA along the wastewater treatment outfitted with Upflow Anaerobic Sludge Blanket (UASB) system evaluated through two sample concentration techniques.

For the first time, we present, i) an account of decay in the genetic material loading of SARS-CoV-2 during Upflow Anaerobic Sludge Blanket (UASB) treatment of wastewater, and ii) comparative evaluation of polyethylene glycol (PEG), and ultrafiltration as virus concentration methods from wastewater for the quantification of SARS-CoV-2 genes. The objectives were achieved through tracking of SARS-CoV-2 genetic loadings i.e. ORF1ab, N and S protein genes on 8th and 27th May 2020 along the wastewater treatment plant (106000 m3 million liters per day) equipped with UASB system in Ahmedabad, India. PEG method performed better in removing materials inhibiting RT-qPCR for SARS-CoV-2 gene detection from the samples, as evident from constant and lower CT values of control (MS2). Using the PEG method, we found a reduction >1.3 log10 reduction in SARS-CoV-2 RNA abundance during UASB treatment, and the RNA was not detected at all in the final effluent. The study implies that i) conventional wastewater treatment systems is effective in SARS-CoV-2 RNA removal, and ii) UASB system significantly reduces SARS-CoV-2 genetic loadings. Finally, PEG method is recommended for better sensitivity and inhibition removal during SARS-CoV-2 RNA quantification in wastewater.

The most eagerly awaited summer of the Anthropocene: A perspective of SARS-CoV-2 decay and seasonal change.

To date, the world perhaps has never waited for the summer so impatiently in the entire Anthropocene, owing to the debate whether increasing temperature and humidity will decrease the environmental endurance of SARS-CoV-2. We present the perspective on the seasonal change on SARS-CoV-2 decay and COVID-19 spread. Our arguments are based on: i) structural similarity of coronavirus with several enteric viruses, and its vulnerability; ii) reports related to decay of those similar transmissible gastroenteritis viruses (TGEV) like norovirus and iii) improvement in the human immunity during summer compared to winter. We present reasons why we can be optimistic about the slowdown of corona in the upcoming summer.