Causative agent of syphilis

Treponema pallidum subsp. pallidum
This organism is the causative agent of endemic and venereal syphilis. This sexual transmitted disease was first discovered in Europe at the end of the fifteenth century, however, the causative agent was not identified until 1905. At one time syphilis was the third most commonly reported communicable disease in the USA. Syphilis is characterized by multiple clinical stages and long periods of latent, asymptomatic infection. Although effective therapies have been available since the introduction of penicillin, syphilis remains a global health problem
Treponema pallidum subsp. pallidum strain Nichols. This strain was originally isolated in 1912 from a neurosyphilitic patient and is virulent.