SPIROCHETES

Question 1

What are the three genera of spirochetes that include human pathogens?

Answer 1

1- Treponema …Treponema pallidum. Syphilis
2- Borrelia …Borrelia recurrentis. Relapsing fever
3- Leptospira …Leptospirosis

Question 2

What is the primary mode of transmission for Treponema pallidum?

Answer 2

Primarily sexually transmitted disease. May be transmitted congenitally.

Question 3

What are the virulence factors of Treponema pallidum?

Answer 3

• Outer membrane proteins promote adherence
• Hyaluronidase may facilitate perivascular infiltration
• Antiphagocytic coating of fibronectin
• Tissue destruction and lesions are primarily result of host’s immune response (immunopathology)

Question 4

What is the characteristic lesion of primary syphilis?

Answer 4

A papule develops at the site of infection and breaks down to form an ulcer with a clean, hard base (‘hard chancre’).

Question 5

What are the symptoms of secondary syphilis?

Answer 5

These consist of a red maculopapular rash anywhere on the body, including the hands and feet, anogenital region, axillas, and mouth.

Question 6

What is the difference between early latent and late latent syphilis?

Answer 6

• First 4 years = Early latent
• Subsequent period = Late latent

Question 7

What are the complications of tertiary syphilis?

Answer 7

• Gummas (soft swelling, granulomatous lesions) which occurs in the connective tissue of the liver, brain, testes, and heart, skin, and bones;
• Degenerative changes in the central nervous system;
• Cardiovascular complications.

Question 8

How is congenital syphilis transmitted?

Answer 8

Congenital syphilis results from transplacental infection. T. pallidum septicemia in the developing fetus and widespread dissemination.

Question 9

What are the diagnostic tests for syphilis?

Answer 9

A- Microscopically
1- Darkfield microscopy
2- Direct Fluorescent Ab-T. pallidum (DFA-TP)
B- Serologic Tests for Syphilis
1 Nontreponemal tests (qualitative & quantitative).
2 Treponemal tests (qualitative).

Question 10

What is the treatment for primary, secondary, or early latent syphilis?

Answer 10

A single intramuscular injection of long acting Benzathine penicillin G (2.4 million units administered intramuscularly) will cure a person who has primary, secondary or early latent syphilis.

Question 11

What is the role of hyaluronidase in Treponema pallidum infection?

Answer 11

Hyaluronidase may facilitate perivascular infiltration.