Virological Quality of Urban Rivers and Hospitals Wastewaters in Addis Ababa, Ethiopia

Human viral pathogens in the wastewater-source water-drinking water continuum: Evidence, health risks, and lessons for future outbreaks in low-income settings

Human viral pathogens, including SARS-CoV-2 continue to attract public and research attention due to their disruption of society, global health, and the economy. Several earlier reviews have investigated the occurrence and fate of SARS-CoV-2 in wastewater, and the potential to use such data in wastewater-based epidemiology. However, comprehensive reviews tracking SARS-CoV-2 and other viral pathogens in the wastewater-water-drinking water continuum and the associated risk assessment are still lacking. Therefore, to address this gap, the present paper makes the following contributions: (1) critically examines the early empirical results to highlight the occurrence and stability of SARS-CoV-2 in the wastewater-source water-drinking water continuum, (2) discusses the anthropogenic and hydro(geo)logical processes controlling the circulation of SARS-CoV-2 in the wastewater-source water-drinking water continuum, (3) discusses the risky behaviour, drivers and high-risk settings in the wastewater-source water-drinking water continuum, (4) uses the available empirical data on SARS-CoV-2 occurrence in the wastewater-source water-drinking water continuum to discuss human health risks from multiple exposure pathways, gendered aspects of SARS-CoV-2 transmission via shared on-site sanitation systems, and (5) develops and risk mitigation strategy based on the available empirical evidence and quantitative human risk assessment data. Finally, it presents a comprehensive research agenda on SARS-CoV-2/COVID-19 to guide the mitigation of future similar outbreaks in low-income settings.

Incidence of Multidrug-Resistant Escherichia coli Harbouring blaTEM and tetA Genes Isolated from Seafoods in Lagos Nigeria

The presence of multidrug-resistant Escherichia coli of fecal origin in seafood is a serious concern. Seafood containing MDR E. coli can serve as a medium for the transfer of resistant bacteria to consumers. The aim of the present study is to isolate and identify multidrug-resistant E. coli and associated resistant genes from selected seafood (catfish, crabs and tilapia fish) purchased from wholesalers and retailers at sea landing areas in Lagos state, Nigeria. A total of two hundred and thirty-eight (238) samples consisting of catfish (52), tilapia fish (78) and crab (108) were collected and investigated for the presence of E. coli from the period of June 2018-April 2019. Colonies that showed metallic sheen were considered presumptive E. coli isolates, and positive isolates were chosen for further confirmed by biochemical methods using IMViC tests, Oxidase test, triple sugar iron agar test and sugar fermentation test. Antimicrobial susceptibility of the isolates to eight classes of antibiotics was determined by disc diffusion methods while amplification of suspected antibiotic resistance genes were done by the polymerase chain reaction (PCR) using specific primers. A total of 105 (44.1%) E. coli were isolated from selected samples by standard microbiological procedures. The grand total of 59 (56.2%) isolates showed multiple antibiotic-resistant patterns. The overall result showed high-level resistance to tetracycline 101/105 (96.1%) and trimethoprim 90/105 (85.7%), cefotaxime 67/105 (42.9%) while the highest susceptibility of 101/105 (96.2%) was recorded for amikacin followed by gentamicin 84/105 (80%), meropenem 75/105 (71.4%), ceftazidime (69.5). The presence of tetA and blaTEM was prevalent among the isolates. Our results indicate that seafood may be a reservoir of β-lactam and tetracycline-resistance determinants.

SARS-CoV-2 in wastewater: Challenges for developing countries

The COVID-19 pandemic that has engulfed the world, has affected the human lives in several aspects. The detection of SARS-CoV-2 in faeces and urine of the infected person, even after viral clearance in the respiratory tract, and its presence in untreated wastewater raises the possibility of fecal-oral transmission in future. The situation is likely to be more aggravated in developing and least developed countries struggling with the problem of ineffective waste disposal system, open defecation, poor sanitation, and limited access to clean drinking water. In this review, the available data on wastewater treatment, sanitation status and healthcare infrastructure from middle- and low-income countries is collected and correlated with the risk associated with the fecal-oral transmission of SARS-CoV-2. The review also highlights the limitation of COVID-19 surveillance through sewage monitoring in these countries owing to the absence of proper sewerage system. An inclusive approach of awareness, prevention, and mitigation from global to the local levels is required to overcome this challenging situation in developing countries.