He tells you that about 4 weeks ago he had a painless lesion in his penis that went away on its own 1. Treponema pallidum, a spirochaete 6-14mm long and 0.5mm wide. The organism cannot be cultured in vitro. Spread is by sexual contact, in utero, and via blood transfusions. The manifestations of syphilis are notoriously diverse.
Early disease is divided into primary and secondary stages.
Early stages are characterized by mucocutaneous lesions. There is then a period of latent infection followed by the tertiary stage, characterized by chronic progressive lesions of the nervous, cardiovascular and musculoskeletal systems. T. pallidum can be seen by dark ground examination of material from the chancre, which is highly infectious. Secondary syphilis Signs and symptoms of secondary syphilis appear 6-8 weeks after the appearance of the primary lesion, which may not have yet healed. Late latent period is the subsequent period up to the development of tertiary disease.