SARS-CoV-2 sewage surveillance in low-income countries: potential and challenges

This paper reviews the recent findings in the detection of SARS-CoV-2 in sewage samples. We discuss how wastewater-based surveillance (WBS) can be used as a complementary tool to help the fight against COVID-19 spread, particularly in low-income countries with low sewage coverage and where the testing coverage is deficient, such as Brazil. One of the major challenges on WBS is the use of different protocols to estimate the number of infected people in a community from the quantification of SARS-CoV-2 in wastewater. Therefore, we assembled and reviewed all the relevant data available to date about this topic. Virus concentration and detection methods were reviewed as well, and some of them can be performed in most of the microbiology and environmental engineering laboratories in low-income countries, as discussed. Moreover, the monitoring and sampling plan should represent the local reality. Thus, we suggest unique strategies for sewage sampling and monitoring in different sewerage network points and the slums, despite the possible logistics difficulties involved. Considering the low levels of sanitation in most urban agglomerates in Brazil, WBS can potentially assume a crucial role as a cost-effective strategy to monitor the circulation of the virus and assess the real prevalence of COVID-19.