2. • The genus Treponema belongs to the family of
Spirochaetaceae and includes several significant
human pathogen species and subspecies. T.
pallidum, is the syphilis pathogen.
3. • Morphology and culture: These organisms are slender
bacteria, 0.2 µ wide and 5–15 µ long; they feature 10–20
primary windings and move by rotating around their
lengthwise axis. Their small width makes it difficult to
render them visible by staining. They can be observed in
vivo using dark field microscopy. Invitro culturing has not
yet been achieved.
4. • Pathogenesis and clinical picture: Syphilis
affects only humans. The disease is normally
transmitted by sexual intercourse. .The
incubation period is two to four weeks. Left
untreated, the disease manifests in several stages:
5. • Stage I (primary syphilis): Hard painless
lesion, later infiltration and ulceration, called
hard chancre. The accompanied by regional
lymphadenitis, also painless. Treponemes can
be detected in the ulcer.
6. • StageII (secondarysyphilis): Generalization
of the disease occurs four to eight weeks after
primary syphilis. Clinical symptoms include
macular or popular skin and mucus membrane
7. • Latent syphilis: Stage of the disease in which
no clinical symptoms are manifested, but the
pathogens are present in the body and serum
antibody tests are positive.
8. • Stage III (tertiary or late syphilis):
manifestations in skin, mucosa, and various
organs. Tissue disintegration is frequent.
Lesions are hardly infectious.
9. • Congenital Syphilis: Transmission of the
pathogen from mother to fetus after the fourth
month of pregnancy. It leads to miscarriage or
birth of severely diseased infant with
numerous treponemes in its organs.
• Pathogen identification: Only detectable in
fluid pressed out of primary chancre, in the
secretions of seeping stage II or in lymph node
biopsies. Methods: dark field microscopy, direct
11. • Antibody assays: Two antibody groups can
1)Anti-lipoidal antibodies (reagain
antibodies): The antigen used is cardiolipin, a
lipid extract from the heart muscle of cattle.
12. 1) Anti-treponema antibodies:
a. Treponema pallidum particle agglutination (TP-PA): The
antigens (treated suspension of Treponema pallidum,
Nichols strain, cultured in rabbit testicles) are coupled to
particles or erythrocytes.
c. Treponema pallidum immobilization test (TPI test).
Living treponemes (Nichols strain) are immobilized by
antibodies in the patient serum.