In what is likely a first in Africa, Health and Wellness ministry officials are pioneering tests on the sewage of Gaborone to ascertain how widespread the coronavirus is in the capital city. The tests will be done alongside the community testing of 22,000 people around the country, an exercise that kicks off on Monday.
The cutting-edge sewage tests have already been done in some developed countries such as the Netherlands, where they helped provide early warning of the pandemic’s presence.
The COVID-19 Task Force Coordinator, Dr Kereng Masupu told MmegiOnline that by using a combination of the community testing, which is at household level and the sewage testing, health authorities would have a greater understanding of the extent of the pandemic in the country.
“We are using two approaches. One is the household sampling and the other is a population census of the sewage system of the cities which have those systems.
“This is a novel way of looking at it. We don’t say a lot about it, but the sewage approach actually samples the whole of Gaborone quietly.
“This will take place with this household testing, alongside it and we will use the two parallel approaches,” he said.
Scientists stress that while sewage testing does not indicate the number of coronavirus cases, it provides useful information on the presence of the pandemic in an area. Studies done in the Dutch city of Amersfoort in February helped authorities prepare for the pandemic before cases spread.
“The detection of the virus in sewage, even when the COVID-19 prevalence is low, indicates that sewage surveillance could be a sensitive tool to monitor the circulation of the virus in the population,” the scientists wrote in a paper published early this month.
More importantly, sewage tests could raise the alarm if the coronavirus resurfaces after it is brought under control, the scientists said. In their paper, the scientists involved in the Netherlands study wrote that in the current pandemic;
“A significant proportion of cases shed the virus with their faeces”.
“The detection of the virus in sewage, even when the COVID-19 prevalence is low, indicates that sewage surveillance could be a sensitive tool to monitor the circulation of the virus in the population,” they wrote.
In an interview with the UK’s Independent newspaper, Dr William Schaffner, Professor of Preventative Medicine and Infectious Diseases at Vanderbilt University School of Medicine, said sewage tests were a useful surveillance mechanism.
“It might be useful following the end of an outbreak. You could continue to sample the sewage for a period of time to see whether the virus has truly gone away.
“That might have additional utility to the other surveillance systems that are ongoing.”
Results from the community testing and sewage sampling are expected to influence whether the government will relax or intensify the lockdown on April 30 when the current one elapses.
Local health authorities involved in the community testing have expressed concern that the original duration of between eight and 10 days for the exercise could extend even beyond the lockdown.
“We need at least 18 days to process the data of the considerable population sample that is enough to inform the decision on the lockdown,” disclosed Dr Morrison Sinvula, Deputy Permanent Secretary, Health Services Management in the Ministry of Health and Wellness.