TREPONEMA PALLIDUM(MSLV

TREPONEMA PALLIDUM (MSLV)

Morphology

• Treponema pallidum is a spiral-shaped bacteria.
• It is a flagellated, non-motile, and anaerobic bacterium.
• Size: 6-15 μm long, 0.1-0.2 μm in diameter.
• Structure: spiral-shaped with a central core and a sheath.
• No capsules or spores are found.

Pathogenesis

• Caused by Treponema pallidum.
• Primary lesion: chancre, a painless, firm, and solitary ulcer at the site of inoculation.
• Secondary stage: skin rash (maculopapular rash), fever, headache, and swollen lymph nodes.
• Latent stage: asymptomatic.
• Tertiary stage: gumma (granulomatous lesions), cardiovascular syphilis, and neurosyphilis.

Life Cycle

1. Initial Infection → Chancre (primary lesion)
2. Inoculation of Treponema pallidum through mucous membranes or minor skin lesions →
3. Bacteria multiply and form a chancre, which is a painless, firm, and solitary ulcer.
4. Secondary stage: bacteria spread through the bloodstream and lymphatic system →
5. Skin rash, fever, headache, and swollen lymph nodes occur.
6. Latent stage: bacteria remain dormant, and the patient becomes asymptomatic.
7. Tertiary stage: bacteria reactivate and cause gumma, cardiovascular syphilis, or neurosyphilis.

Clinical Manifestations

• Primary syphilis: chancre (painless ulcer), usually on the genitals or oral cavity.
• Secondary syphilis: maculopapular rash, fever, headache, and swollen lymph nodes.
• Latent syphilis: asymptomatic.
• Tertiary syphilis: gumma (granulomatous lesions), cardiovascular syphilis, and neurosyphilis.

Laboratory Diagnosis

• Dark-field microscopy: examine a sample from a chancre or rash for spirochetes.
• Serological tests:
  • VDRL (Venereal Disease Research Laboratory) test.
  • RPR (Rapid Plasma Reagin) test.
  • FTA-ABS (Fluorescent Treponemal Antibody Absorption) test.
  • TP-PA (Treponema pallidum particle agglutination) test.

Memory Trick

• "CINDY" for Chancre, Inoculation, Nascent bacteria, Dissemination, and Years of hiding (Latent stage)
• "CATS" for Chancre, Acanthosis (rash), Tachycardia (fever), and Swollen lymph nodes (secondary stage)
• "GUM" for Gumma, Uterine, and Myocardial damage (tertiary stage)