One Year of Wastewater Surveillance in South Africa Supporting COVID-19 Clinical Findings Across Two Waves of Infection

• Published in: Microorganisms (Basel) 2024-11, Vol.12 (11), p.2230
• Main Authors: Street, Renée, Mathee, Angela, Reddy, Tarylee, Mahlangeni, Nomfundo T, Mangwana, Noluxabiso, Nkambule, Sizwe, Webster, Candice, Dias, Stephanie, Sharma, Jyoti Rajan, Ramharack, Pritika, Louw, Johan, Surujlal-Naicker, Swastika, Berkowitz, Natacha, Mdhluli, Mongezi, Gray, Glenda, Muller, Christo, Johnson, Rabia
• Format: Article
• Language: English
• Subjects: Communication; COVID-19; environmental epidemiology; Epidemiology; Gene expression; Genomes; Health aspects; Health surveillance; Impact analysis; Laboratories; Medical research; Medicine, Experimental; Nucleocapsids; Pandemics; Public health; Purification; Real time; Ribonucleic acid; RNA; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Sewage; South Africa; Surveillance; Trends; Viral diseases; viral RNA; Wastewater; Wastewater treatment; Wastewater treatment plants; Water treatment plants
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms12112230

Wastewater-based epidemiology (WBE) has been an important tool for the detection of COVID-19 outbreaks. The retrospective analysis of COVID-19 data is vital to understand the spread and impact of the virus as well as to inform future planning and response efforts. In this study, we evaluated the SARS-CoV-2 RNA levels in wastewater from 21 wastewater treatment plants (WWTPs) in the City of Cape Town (South Africa) over a period of 12 months and compared the (inactive) SARS-CoV-2 viral RNA in wastewater between wave 2 (November 2020 to January 2021) and wave 3 (June 2021 to September 2021). The SARS-CoV-2 RNA expression was quantified in wastewater using quantitative real-time PCR (qRT-PCR) by targeting the nucleocapsid (N) gene, and the resultant signal was normalized to the WWTP design capacity and catchment size. Our findings show that the maximum SARS-CoV-2 RNA signal was significantly higher in wave 3 than in wave 2 ( < 0.01). The duration of wave 3 (15 weeks) was longer than that of wave 2 (10 weeks), and the wastewater surveillance data supported the clinical findings, as evidenced by the two distinct waves. Furthermore, the data demonstrated the importance of long-term wastewater surveillance as a key indicator of changing trends.