Exploration of wastewater surveillance for Monkeypox virus

The sudden emergence and spread of Monkeypox in non-endemic parts of the world is currently not well understood. Infections are often mis-diagnosed and surveillance strategies are scarce. Wastewater-based surveillance (WBS) of human Monkeypox virus (MPXV) can help supplement our current clinical surveillance and mitigation efforts. WBS has shown to be an effective tool in monitoring the spread of other infectious pathogens, such as SARS-CoV-2 and its variants, and has helped guide public health actions. In this study, we describe how WBS can be used to detect MPXV in wastewater. We conducted WBS for MPXV in 22 wastewater treatment plants (WWTPs) over a period of 14 weeks. Nucleic acids were extracted using the MagAttract PowerMicrobiome DNA/RNA extraction kit. Three real-time qPCR assays were assessed for the detection of MPXV in wastewater. These included the G2R assays (G2R_WA and G2R_G) developed by the Centers for Disease Control and Prevention (CDC) in 2010, as well as an in-house-developed assay (G2R_NML). The G2R_G (generic) assay was designed to detect both the Congo and West African clades (re-named to Clades one and two, respectively) of viruses while the G2R_WA assay was designed to detect the West African clade (Clade one). The G2R_NML assay was designed using reference genomes of the 2022 MPXV outbreak. Our results show that all three assays have similar limits of detection and are all able to detect the presence of MPXV in wastewater. Following detection through real time qPCR, Sanger sequencing was performed on the resulting amplicon products, with the assembled contigs then undergoing analysis using nucleotide Basic Local Alignment Search Tool (BLAST). Due in part to the longer amplicon size of the G2R_NML assay, a significantly greater number of positive detections were identified as originating from MPXV compared to the CDC G2R assays. The ability to detect trace amounts of MPXV in wastewater as well as obtain Sanger sequence confirmation, has allowed for the successful surveillance of this virus in wastewater.