Longitudinal wastewater-based surveillance of SARS-CoV-2 during 2023 in Ethiopia

• Main Authors: Daniel Abera Dinssa (Author), Gebremedhin Gebremicael (Author), Yohannes Mengistu (Author), Noah C. Hull (Author), Dinknesh Chalchisa (Author), Girma Berhanu (Author), Atsbeha Gebreegziabxier (Author), Ashley Norberg (Author), Sarah Snyder (Author), Sarah Wright (Author), Waktole Gobena (Author), Adugna Abera (Author), Yohannes Belay (Author), Dawit Chala (Author), Melaku Gizaw (Author), Mesay Getachew (Author), Kirubel Tesfaye (Author), Mesfin Tefera (Author), Mahlet Belachew (Author), Tegegne Mulu (Author), Solomon Ali (Author), Abebaw Kebede (Author), Daniel Melese (Author), Saro Abdella (Author), Tobias F. Rinke de Wit (Author), Yenew Kebede (Author), Mesay Hailu (Author), Dawit Wolday (Author), Masresha Tessema (Author), Getachew Tollera (Author)
• Format: Book
• Published: Frontiers Media S.A., 2024-10-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 2296-2565; 10.3389/fpubh.2024.1394798
• Keywords: COVID-19; SARS-CoV-2; qRT-qPCR; wastewater treatment plants; wastewater-based epidemiology; Public aspects of medicine; RA1-1270
• Source: Frontiers in Public Health, Vol 12 (2024)

IntroductionAlthough wastewater-based epidemiology (WBE) successfully functioned as a tool for monitoring the coronavirus disease 2019 (COVID-19) pandemic globally, relatively little is known about its utility in low-income countries. This study aimed to quantify severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in wastewater, estimate the number of infected individuals in the catchment areas, and correlate the results with the clinically reported COVID-19 cases in Addis Ababa, Ethiopia.MethodsA total of 323 influent and 33 effluent wastewater samples were collected from three Wastewater Treatment Plants (WWTPs) using a 24-h composite Moore swab sampling method from February to November 2023. The virus was captured using Ceres Nanotrap® Enhancement Reagent 2 and Nanotrap® Microbiome A Particles, and then nucleic acids were extracted using the Qiagen QIAamp Viral RNA Mini Kit. The ThermoFisher TaqPath™ COVID-19 kit was applied to perform real-time reverse transcriptase polymerase chain reaction (qRT-PCR) to quantify the SARS-CoV-2 RNA. Wastewater viral concentrations were normalized using flow rate and number of people served. In the sampling period, spearman correlation was used to compare the SARS-CoV-2 target gene concentration to the reported COVID-19 cases. The numbers of infected individuals under each treatment plant were calculated considering the target genes' concentration, the flow rate of treatment plants, a gram of feces per person-day, and RNA copies per gram of feces.ResultsSARS-CoV-2 was detected in 94% of untreated wastewater samples. All effluent wastewater samples (n = 22) from the upflow anaerobic sludge blanket (UASB) reactor and membrane bioreactor (MBR) technology were SARS-COV-2 RNA negative. In contrast, two out of 11 effluents from Waste Stabilization Pond were found positive. Positive correlations were observed between the weekly average SARS-CoV-2 concentration and the cumulative weekly reported COVID-19 cases in Addis Ababa. The estimated number of infected people in the Kality Treatment catchment area was 330 times the number of COVID-19 cases reported during the study period in Addis Ababa.DiscussionThis study revealed that SARS-CoV-2 was circulating in the community and confirmed previous reports of more asymptomatic COVID-19 cases in Ethiopia. Additionally, this study provides further evidence of the importance of wastewater-based surveillance in general to monitor infectious diseases in low-income settings.ConclusionWastewater-based surveillance of SARS-CoV-2 can be a useful method for tracking the increment of COVID-19 cases before it spreads widely throughout the community.