Sporadic detection of vaccine-derived poliovirus type 2 using next-generation sequencing in Canadian wastewater in August of 2022

Figures

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  Fig. 1. Summary of poliovirus detections in collected wastewater sampled between May 2022 and July 2024. Summary of the weeks when specimens were collected for each collection site. The dates represent the Monday of the weeks during which specimens were collected for poliovirus testing. The exact collection dates can be found in Supplemental Table S2. Samples for all targeted sites were specifically collected for poliovirus investigation while samples from the north and south interceptor pipes were re-purposed COVID-19 surveillance specimens. Estimated population serviced by each collection site is indicated. Poliovirus detections represent both real-time PCR (RT-PCR) poliovirus positive signals plus sequence confirmation.

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  Fig. 2. Maximum-likelihood phylogeny of the Poliovirus 2 capsid sequences. Nucleotide sequences of select poliovirus 2 VP1-VP4 coding region were obtained from the NCBI GenBank database. Red text highlights the poliovirus type 2 isolate sequence obtained from Canadian wastewater in 2022. The tree was rooted with a Sabin 2 reference. SH-like branch support values are indicated at the nodes and the maximum-likelihood scale bar indicates average residue substitution per site. ENV = environmental.

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  Fig. 3. Mutation profile for the WW22-4017 poliovirus isolate. (A) Nucleotide and (B) amino acid mutation profiles of WW22-4017 (PQ641085) as compared to Sabin 2 (AY184220.1), USA-NY-22 (OP265178.1) and London UK environmental sample (OP410366.1). Mutations resulting in enhanced neurovirulence are depicted. UTR = untranslated region; P1 = polyprotein 1; VP1 = viral protein 1; P2 = polyprotein 2; P3 = polyprotein 3; WW = wastewater.

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  Fig. 4. Mutation profile of the VP1 region sequenced by Nanopore and Sanger directly from the wastewater specimen WW22-4017. (A) Nucleotide and (B) amino acid differences as compared to Sabin 2 (AY184220.1) are depicted. Whole genome sequence data of WW22-4017 poliovirus isolate (PQ641085) is included for comparative purposes. Differences highlighted in red are the common ones shared with USA-NY-22. Sanger_WW (PQ641087), Nanopore_rep1 (PQ641089) and Nanopore_rep2 (PQ641090). WW = wastewater.