 "T. p. pallidum" is a motile spirochaete that is generally acquired by close sexual contact, entering the host via breaches in squamous or columnar epithelium.The organism can also be transmitted to a fetus by transplacental passage during the later stages of pregnancy, giving rise to congenital syphilis.The helical structure of "T. p. pallidum" allows it to move in a corkscrew motion through mucous membranes or enter minuscule breaks in the skin.