Traces of non-infectious Delta variant discovered in Western Cape wastewater

The South African Medical Research Council (SAMRC) has detected the Covid-19 Delta variant in wastewater in the City of Cape Town as well as several towns throughout the Western Cape.

The detection was found through the SAMRC’s Wastewater Surveillance Programme.

The SAMRC said a correlation had been found between viral load in wastewater and subsequent Covid-19 cases.

“For the past two months, scientists have been screening for the presence of mutations associated with the Alpha and Beta variants in wastewater and found both the Alpha and Beta variants, with the Beta variant being predominant,” said Dr Rabia Johnson, deputy director of the SAMRC’s Biomedical Research & Innovation Platform (BRIP).

This week, the team acquired the reagents to also test for the Delta variant.

It detected it as the dominant variant in the Breede Valley towns of Worcester, Rawsonville, Touws River and De Doorns, in the Theewaterskloof municipal towns of Bot River and Villiersdorp, as well as in 19 wastewater treatment plants in the Cape Town Metropole.

The team said it had seen sharp increases in SARS-CoV-2 viral loads in most wastewater treatment plants, monitored by the SAMRC wastewater surveillance and research programme.

Dr Mongezi Mdhluli, Chief Research Operations Officer at the SAMRC, said: “The Delta variant is highly contagious and in light of the findings from the SAMRC Wastewater Surveillance Programme, and their implications, we implore all in South Africa to adopt the highest level of precaution possible to disrupt the transmission of Covid-19.”

The City’s mayoral committee member for community and health services, Zahid Badroodien, said they were aware of the detection.

He said:It is important to note that the viral remnants found in wastewater are non-infectious. SARS-Cov-2 viral remnants have been found in all wastewater treatment works since we have started monitoring. Recently the MRC have detected the Delta variant in all treatment plants apart from Zandvliet.

The Western Cape government’s Environmental Affairs and Development Planning Department said it was crucial to note that the detected traces of the variant found were fragments of the virus, which was not infectious in wastewater as it was no longer a living virus.

“The surveillance of wastewater acts as an effective additional early warning system to pick up any increases in virus load in a specific area. This assists authorities to put management actions in place to address any increase in a number of positive cases within such an area,” the department said in a statement.