Other Treponema pallidum infections
Infection with other T. pallidum subspecies (i.e., T. pallidum subsp. pertenue, T. pallidum subsp. endemicum, and T. carateum) is acquired through contact with infected skin. These may result in a simple rash, but may progress and cause disfiguring skin lesions. Unlike syphilis, these infections are not considered sexually transmitted. Long-term infection can lead to deformation of bone and nasopharyngeal tissue. Infection with any of these subspecies can also cause seroreactivity for treponemal and nontreponemal tests used for diagnosis of syphilis; therefore, it is important to obtain a history of sexual and nonsexual exposures and consider T. pallidum subspecies in persons from areas where these infections are endemic.