Figure 2. Molecular characterization of VDPV-2s isolated in the Central African Republic in 2019. A) Phylogram of the VP1-encoding sequence drawn by using the maximum-likelihood method based on the data-specific model. Alternating blue and red indicate evolutionary branches (A–L); open circles indicate sequences of VDPVs from patients with acute flaccid paralysis circles; closed circles indicate sequences of VDPVs from healthy children; black triangles indicate sequences of VDPVs from environmental samples. The district where the isolate was sampled and the recombinant pattern the isolate belongs to (patterns 1–12 or nonrecombinant [Figure 2, panel B]) are indicated; asterisks indicate isolates that have not been fully sequenced. Scale bar indicates nucleotide substitutions per site. B) Schematic representation of the genomic patterns of the VDPVs. Top row shows poliovirus genetic organization, with the main open reading frame flanked by the 5′ and 3′ untranslated regions (UTRs). Approximate locations of the recombination sites (1–12 on left) are shown. Sequences with different colors differ by <3%. Letters in parentheses on the right indicate the VP1 branches where each recombinant pattern can be found. NR, no recombination. C) Similarity plot drawn by comparing the sole genome of pattern 5 with genomes of patterns 3 (green), 4 (red), and 6 (blue) in the 3′ half of the genome. Sliding window width, 200 nt; step distance, 20 nt. VDPV-2s, type 2 vaccine-derived polioviruses; VP1, viral capsid protein 1.