The novel coronovirus SARS-CoV-2 spreads primarily via respiratory droplets. Such droplets landing on surfaces can also spread infection.
Recent investigations, according to a review by Indian Institute of Technology Kharagpur researchers, show the presence of live virus in stool samples, suggesting a possible faecal–oral transmission of COVID-191.
Several studies have recorded patients with no trace of the novel coronavirus in their respiratory tracts. But the virus was found in their faeces and gastrointestinal tracts. The review cites reports that have found the live virus in the anal swabs or blood samples of patients while their oral swabs tested negative. These patients were likely to be considered COVID-19 negative in routine surveillance despite posing a threat to other people, according to the researchers.
Infected faeces can easily contaminate wastewater generated from hospitals, quarantine centres and domestic households with COVID-19 cases. It can elevate the concentration of the virus in water bodies receiving untreated sewage. SARS-CoV, an earlier reported coronavirus, can survive up to 14 days at 4 °C, and for only 2 days at 20 °C in untreated sewage. The novel coronovirus has also been detected in untreated sewage worldwide.
With around 1.8 billion people worldwide using faecal-contaminated source as drinking water, the risk of transmission of COVID-19 through untreated sewage is expected to increase by several folds, the researchers say.
1. Bhowmick, G. D. et al. Coronavirus disease 2019 (COVID-19) outbreak: some serious consequences with urban and rural water cycle. npj Clean. Water. 3, 32 (2020)