Possible transmission of viruses from contaminated human feces and sewage: Implications for SARS-CoV-2

Humanity has experienced outbreaks by viruses such as severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) in 2003, Eastern respiratory syndrome coronavirus (MERS-CoV) in 2012, Ebola virus in 2014 and nowadays SARS-CoV-2. While clinicians seek for a vaccine to reduce the epidemic outbreak, environmental engineers need to understand consequence of virus entity in sewage given the reported persistency of viruses in human feces and sewage environments for more than days. Herein, we discuss about concerns associated with virus occurrence in human feces and sewage, with attention to the possible SARS-CoV-2 transmission routes, based on the review of recent studies on SARS-CoV-2 as well as the previous pandemic events. Given the reported environmental stability of coronavirus, the feces- and sewage-derived transmission routes may be of importance to prevent unprecedented spread of coronavirus disease 2019 (COVID-19) particularly in developing countries. However, so far, limited number of studies detected infectious SARS-CoV-2 even in human feces, whereas a number of virus RNA copies were identified in both feces and sewage specimens. Therefore, uncertainty remains in the possibility of this transmission pathway, and further investigation is warranted in future studies, for example, by increasing the number of specimens, examining the effectiveness of methods for viral viability test, considering the patient medical history, and so forth.