Organism: Treponema pallidum, spirochete, cannot be cultured

Route: anogenital/oral transmission

Incubation

• primary: 9-90 days (3 weeks)
• secondary: 2-24 weeks (6 weeks)
• tertiary: 5-35 years

Transmission

• sexual: access to subcut via microscopic abraisions during intercourse
  • ~50% when symptomatic
  • only transmissible by sex for first 2 years infection
  • transmissible during primary or secondary syphilis with 30% efficiency
• some vertical (pregnancy)

Pathophys: early local replication and infection in regional draining lymph nodes with later dissemination

Epidemiology

• ATSI 6x gen pop
• MSM

Clinical Findings

50% Asymptomatic/latent