Spirochaetes

• What are spirochetes?

  Thin-walled, flexible, spiral rods
• How do spirochetes move?

  Through undulation of axial filaments
• Which genera of spirochetes are of medical importance?

  Treponema, Borrelia, and Leptospira
• How are Treponemes and Leptospira observed?

  Only by dark-field microscopy or immunofluorescence
• How are Borreliae observed?

  Under light microscope after staining
• What are the types of motility in spirochetes?

  1. Flexion and extension
  2. Corkscrew-like rotatory movement
  3. Translatory
• What disease does Treponema pallidum cause?

  Syphilis
• What is the epidemiology of syphilis?

  It occurs worldwide and is increasing
• Who has seen an increase in syphilis incidence?

  Men who have sex with men
• How many new cases of syphilis does WHO estimate annually?

  12 million
• How is T. pallidum transmitted?

  From lesions of skin or mucous membranes
• What is the main mode of transmission for T. pallidum?

  Mainly by sexual contact
• Can T. pallidum be transmitted transplacentally?

  Yes, from mother to fetus
• What does T. pallidum infect in the body?

  The endothelium of small blood vessels
• What is the consequence of T. pallidum infection?

  Causes endarteritis in small blood vessels
• How does immunity to syphilis function?

  Immunity is incomplete; antibodies don't stop progression
• What primarily causes tissue destruction in syphilis?

  The patient's immune response
• How long can T. pallidum persist in the host?

  For decades despite immune response
• What are the four stages of syphilis?

  1. Primary stage: Chancre on genitalia (2-10 weeks)
  2. Secondary stage: Moist lesions (2-12 weeks)
  3. Latent stage: Asymptomatic but transmissible
  4. Tertiary stage: Chronic granulomas after decades
• What characterizes primary syphilis?

  Painless chancre on genitalia in 2-10 weeks
• What is a typical feature of a syphilitic chancre?

  Shallow ulcer with a rolled edge
• What occurs alongside a chancre in primary syphilis?

  Regional lymphadenopathy, usually bilateral
• What happens to the ulcer in primary syphilis?

  Heals spontaneously but spirochetes spread
• What occurs in secondary syphilis?

  Spirochetes disseminate leading to widespread lesions
• What are the symptoms of secondary syphilis?

  Mucopapular rash, fever, malaise, lymphadenopathy
• What are condylomata lata?

  Moist lesions on the genitals in secondary syphilis
• What happens to early syphilis cases?

  1. 1/3 cure without treatment
  2. 1/3 progress to latent stage
  3. 1/3 progress to tertiary syphilis
• What characterizes latent syphilis?

  Asymptomatic but positive serologic tests
• What occurs during early latent syphilis?

  Reappearance of symptoms and infectiousness
• What is tertiary syphilis?

  A slowly progressive, destructive inflammatory disease
• What are gummas?

  Chronic granulomas in tertiary syphilis
• Are patients with tertiary syphilis infectious?

  No, they are non-infectious
• What is the immunity status in tertiary syphilis?

  Immunity is incomplete; antibodies don't stop progression
• What happens to infants with congenital syphilis?

  They may have mucocutaneous lesions and other symptoms
• What should be done for pregnant women regarding syphilis?

  They should be tested at least twice during pregnancy
• What are the laboratory diagnosis methods for syphilis?

  1. Direct methods: Demonstration of spirochetes
  2. Indirect methods: Detection of antibodies in serum
• What are direct methods for diagnosing syphilis?

  Demonstration of spirochetes in lesions
• What are indirect methods for diagnosing syphilis?

  Detection of antibodies in patient serum
• What is the Fontana stained preparation used for?

  To examine spirochetes under light microscope
• How are spirochetes identified in unstained preparations?

  By their characteristic cork-screw motility