British Study Finds COVID-19 Unlikely to Spread by Fecal-Oral Route

Research funded by the UK Research and Innovation Project, Emerging Issues

British researchers look at the dangers of working around raw sewage. They find SARS-CoV-2 is unlikely to be spread by sewage.

“Overall, we conclude that while virus particles contained in respiratory droplets are known to be highly infectious, evidence suggests that feces and urine probably contain low levels to no infectious particles. In comparison to respiratory particles, they are also less likely to be spread during daily life, being confined largely to toilets and other enclosed environments. This may subsequently lead to contamination of hands, surfaces, food and water; however, in most cases the levels of contamination are likely to be low where good hygiene and sanitation is practiced. Despite this, the possibility of infection by contamination of the oral cavity, respiratory mucosa and eyes cannot be entirely discounted.”

“At present, there are many uncertainties in the survival of SARS-CoV-2 during its passage through the sewer pipe network. CoVs are not thought to survive well in aqueous environments, especially in comparison with other viruses which can persist for months (e.g. poliovirus, norovirus; Seitz et al., 2011). This is supported by studies in which SARS-CoV-2 RNA can be readily detected by qPCR in wastewater leaving hospitals, but which has yet to be found to contain infectious virus (Wang et al., 2005bZhang et al., 2020eWang et al., 2020d). In fact, a recent study suggests that levels of infectious virus were not significant in wastewater and receiving rivers, indicating the effectiveness of wastewater treatment, combined with the natural loss of viral integrity (Rimoldi et al., 2020).”

“Current evidence suggests that the levels of SARS-CoV-2 are greatly lowered during wastewater treatment, suggesting that the virus is either degraded or becomes associated with the solids fraction during flocculation (Wang et al., 2020d). This is consistent with studies showing a 2 to 3 log10 removal efficiency in viral RNA abundance when comparing viral levels in influent and effluent (Wurtzer et al., 2020aWurtzer et al., 2020b) and the accumulation of SARS-CoV-2 in the sludge fraction (Peccia et al., 2020Alpaslan Kocamemi et al., 2020).  If the sludge (biosolids) fraction is treated (e.g. pasteurized, heat-dried, alkali-lime treated), as per the legislative requirement in many countries, this should pose no further risk to human health. ”

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