Table 1. Treponema pallidum subsp. pertenue strains used in this study.

	Strain name	Source	Location	Year of isolation	Ref.
Human isolates of T.p. pertenue	Gauthier a	Skin lesion	Nigeria	1963	[23]
	CDC1b	Skin lesion	Densuso, Ghana	1980	[24]
	CDC2b	Skin lesion	Akorabo, Ghana	1980	[24]
	Samoa D c	Skin	Western Samoa	1953	[25]
	Samoa Fc	Skin	Western Samoa	1953	[25]
	Ghana051d	Unknown	Ghana	1988	[26]
Simian isolate	Fribourg-Blanc c	Lymph node	Guinea	1966	[27]

^a Provided by Peter Perine, Centers for Diseases Control and Prevention, Atlanta, GA.

^b Provided by Robert George and Victoria Pope, Centers for Disease Control and Prevention, Atlanta, GA.

^c Provided by Paul Hardy and Ellen Nell, Johns Hopkins University, Baltimore, MD.

^d Provided by Leo Schouls, National Institute for Public Health and Environment, Bilthoven, and Gerda Noordhoek, Public Health Laboratory, Friesland, The Netherlands. DNA only, no known isolate in existence.