The major risk arising from Covid-19 is the fact that people can be infected but show no symptoms. It is these asymptomatic carriers that are the vectors accelerating infection in society.
Dr Anthony Turton from the Centre for Environmental Management at the University of the Free State (UFS) says since the government cannot test every citizen in the country, the answer lies in sewage surveillance.
In a statement by the UFS, Turton explains that South Africa has 824 wastewater treatment works, and each of these serves a population of known size. By taking samples of sewage according to a defined protocol, it is now technically possible to determine the viral load of the entire population in the catchment area of that sewage works.
This data can be compared weekly, and from this can be determined if the total viral load is increasing or decreasing.
According to Turton, this is much easier to do than the individual testing of millions of citizens. He explains that the virus has a specific structure that gives it a number of properties.
“What is known to scientists, but not yet apparent to the public, is that the virus is shed in human waste. This is known as viral shedding, and is now known to result in a traceable presence in both urine and faeces before a patient manifests with symptoms and after a patient has been treated.
“This does not mean that the virus is still infectious, although there is some mention of faecal-oral transmission in peer-reviewed literature, at least of the SARS virus.”
Turton says it is the evolution of technology that is capable of detecting minute elements of the virus found in human waste. This technology has been successfully used in the Netherlands and is now being rolled out in other developed countries.
The right to use this technology has been secured for South Africa by the SA Business Water Chamber, a non-profit organisation, which entered into an agreement with KWR, the Dutch laboratory that has refined the technique. It is now being made available to any laboratory, privately owned, university owned or part of a national science council, with the intention of supporting decision-making by government.
This will be of critical importance as the government decides to open up the economy, because sewage surveillance can detect a second wave before it is manifested as people reporting to doctors with symptoms.
He explains that any university with PCR capabilities can become a certified user of this technology, as can any commercial laboratory being rolled out as a humanitarian issue rather than a commercial one, even if it has an impact on the recovery of the economy.