Gel and quantitative polymerase chain reaction (PCR) assays utilizing both existing and new PCR primers. A, Gel picture showing PCR products for the genomic DNA (gDNA) of a Solomon Islands (SI) sample WP0022.7liq, and a non-SI sample, Treponema pallidum subsp pertenue Gauthier, with the use of the generic forward and reverse primers as indicated. The reverse primer of the Centers for Disease Control and Prevention (CDC) 2015 real-time (RT) PCR assay is labeled reverse primer in Figure 2 . Forward primer (2015 CDC RT-PCR): 5ʹ-CGGCCACCAACTTGGGATTGAC-3ʹ. Reverse primer (2015 CDC RT-PCR): 5ʹ-CGTACACCGAACCTTTGTCTT-3ʹ. Reverse primer (modified PCR-1): 5ʹ- GTGCGGTGAGCCCGGCGTT-3ʹ. Reverse primer (modified PCR-2): 5ʹ-GTGAGCCCGGCGTT-3ʹ. B, Quantitative PCR amplification curves of new PCR products obtained for the gDNA of the non-SI sample, an SI sample, and both samples (all as in A) combined by using specific reverse primers. Forward primer (2015 CDC RT-PCR): 5ʹ-CGGCCACCAACTTGGGATTGAC-3ʹ. Probe: 5ʹ-FAM-GCTGCAAGGAGAAGTCCTGCTGC-TAMRA-3ʹ. Reverse primer (2015 CDC real-time PCR): 5ʹ-CGTACACCGAACCTTTGTCTT-3ʹ. Reverse primer (modified PCR-2): 5ʹ-GTGAGCCCGGCGTT-3ʹ. Abbreviations: ∆Rn, normalized reporter signal; CDC, Centers for Disease Control and Prevention; DDW, double distilled water; RT-PCR, real-time polymerase chain reaction; SI, Solomon Islands.