SARS-CoV-2 in the environment: Contamination routes, detection methods, persistence and removal in wastewater treatment plants.

The present study reviewed the occurrence of SARS-CoV-2 RNA and the evaluation of virus infectivity in feces and environmental matrices. The detection of SARS-CoV-2 RNA in feces and wastewater samples, reported in several studies, has generated interest and concern regarding the possible fecal-oral route of SARS-CoV-2 transmission. To date, the presence of viable SARS-CoV-2 in feces of COVID-19 infected people is not clearly confirmed although its isolation from feces of six different patients. Further, there is no documented evidence on the infectivity of SARS-CoV-2 in wastewater, sludge and environmental water samples, although the viral genome has been detected in these matrices. Decay data revealed that SARS-CoV-2 RNA persisted longer than infectious particle in all aquatic environment, indicating that genome quantification of SARS-CoV-2 does not imply the presence of infective viral particles. In addition, this review also outlined the fate of SARS-CoV-2 RNA during the different steps in the wastewater treatment plant and focusing on the virus elimination along the sludge treatment line. Studies showed complete removal of SARS-CoV-2 during the tertiary treatment. Moreover, thermophilic sludge treatments present high efficiency in SARS-CoV-2 inactivation. Further studies are required to provide more evidence with respect to the inactivation behavior of infectious SARS-CoV-2 in different environmental matrices and to examine factors affecting SARS-CoV-2 persistence.

A review on mpox (monkeypox) virus shedding in wastewater and its persistence evaluation in environmental samples

Since May 2022, an outbreak of mpox (formerly known as monkeypox) has been spreading in non-endemic countries and this disease is caused by a mpox virus (MPXV) belonging to Orthopoxvirus genus of the Poxviridae family. Public health surveillance is essential to assess the disease prevalence and spread in the populations. In this purpose, wastewater surveillance has proved to be an effective and affordable tool to detect and monitor disease threats and outbreaks, such as SARS-CoV-2, poliovirus, and other viruses. Prior to the current mpox outbreak, previous studies suggested that MPXV shedding is possible after viral genome and infectious particles were detected in the feces of infected animals. On the other hand, using metagenomic and sequencing approaches to assess the diversity of human viral pathogens in wastewater, contigs assigned to orthopoxviruses and poxviruses were among the most abundant contigs detected in collected samples. Recently, MPXV DNA has been detected in wastewater samples from wastewater treatment plants in cities and airports in the United States, the Netherlands, Italy, France, and Spain. It has long been reported that poxviruses are stable in the environment for long periods and might represent as a source of transmission. However, the stability of MPXV in the environment is unknown and the presence of infectious MPXV in wastewater has not yet been determined. The present work is devoted to reviewing past and recent advances in MPXV detection in wastewater. It also addressed the survival data of orthopoxviruses, which may be of interest to evaluate the persistence of MPXV species in environmental matrices.