INTRODUCTION : Ongoing pandemic of coronavirus disease (COVID-19) caused by a new beta coronavirus named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has warranted a global responsibility for its prevention and control. The use of an environmental approach called wastewater-based epidemiology (WBE) for virus detection has proved to be an additional tool to support COVID-19 prevention activities. Among the several methods available, skimmed milk flocculation method has proven to be simple and effective in low-resource settings.
METHODS : In the study period between 11 July – 12 September 2022, 227 wastewater samples from 40 different samplings sites from 4 zones of Trichy City were analyzed using the Skimmed milk flocculation technique. The isolation and detection of SARS COV-2 in wastewater were done by the COSARA kit using Open System real-time PCR.
RESULTS : Out of the 227 samples,92 (40.5%) tested positive for SARS COV-2 virus RNA. Mean Ct values for the RdRp gene were 35.5 and 34.2 for the E gene. Samples collected from all 4 zones and 37 (92.5%) wards showed positivity. There was no significant difference observed between the SARS Cov-2 waste water positivity (p=0.6) and mean Ct values of RdRp (p=0.9) and E Gene(p=0.1) between different zones of the city.
CONCLUSION : Skimmed milk flocculation technique used in the present study had advantages like yielding faster results, ease of use, and non-requirement of robust laboratory infrastructure which matched well with its use in other settings further validating its utility in low resource settings and as a routine surveillance measure.