XIX. SYPHILIS SEROLOGY

SYPHILIS SEROLOGY

A. Causative Agent

• _____ subsp. _____, a spirochete

• Transmitted by _____ (including sexual contact) and ____

• Treponema pallidum ‘;  pallidum

• direct contact ; across the placenta

Incubation period:

• T. pallidum enters the body, reaches the _____, and is disseminated to all _____.

• This early asymptomatic phase lasts _____

• bloodstream ; organs

• 10 days to 10 weeks

Primary syphilis

• The initial lesion is a painless, nonbleeding ulcer called a ____.

• It appears, on average, ____ after the initial infection.

• chancre

• 2–3 weeks

Primary syphilis

• Within _____ after the chancre appears, ___ near the portal of entry enlarge, for example, the groin in sexually transmitted cases.

• Antibodies are produced_____ after the chancre appears.

• Darkfield analysis of lesion demonstrates _____.

• 1 week ; lymph nodes

• 1–4 weeks

• spirochetes

Secondary syphilis

• Symptoms last _____.

• ____ are present throughout the body during this stage

• _____ develop on mucous membranes.

• Serologic tests are _____

• 4–6 weeks

• Spirochetes

• Ulcers

• positive

• Symptoms include skin rash, low-grade fever, malaise, pharyngitis, weight loss, arthralgia, and lymphadenopathy.

Secondary syphilis

Stage of syphilis with no signs or symptoms

Latent syphilis

Latent syphilis

• Nontreponemal and treponemal serologic tests are ____

• _______ (infection occurred within the past 12 months): One in four individuals relapses into _____.

• _____ (infection occurred more than 12 months ago): The patient is resistant to reinfection and to relapses.

• positive.

• Early latent syphilis ; secondary syphilis

• Late latent syphilis ; 

Symptoms occur 2–40 years after initial infection

Tertiary syphilis

Tertiary syphilis

• _____ (syphilis lesions due to hypersensitivity reaction to treponemal antigens) are found throughout the body.

• Syphilitic aortitis, aortic valve insufficiency, and thoracic aneurysm are possible.

• ______ can cause blindness and senility

• Gummas

• Neurosyphilis

Congenital syphilis

• The outcome depends on the stage of the mother’s disease—_____ syphilis causing the worst outcome—and the age of the fetus at time of infection

• If the mother receives treatment during the _____ of pregnancy, congenital syphilis is usually avoided.

• primary or secondary

• first 4 months

What are the stages of disese for syphilis?

1. Incubation period 

2. Primary syphilis

3. Secondary syphilis

4. Latent syphilis

5. Tertiary syphilis

6. Congenital syphilis

• Treponema pallidum is detected using _____ of material from lesions.

• Material from the ____ should not be tested because T. pallidum cannot be differentiated from _____ spirochetes.

• darkfield microscopy or silver stain

• oral cavity '; commensal

________ test:

• A fluorescence-labeled antibody is used to detect T. pallidum in lesions.

• The test is specific for pathogenic Treponema and can therefore be used on oral and rectal specimens, but it cannot distinguish among the causative agents of syphilis, yaws, pinta, and endemic syphilis.

Direct fluorescent antibody-T. pallidum (DFA-TP)

Treponema pallidum infection causes the host to produce nonspecific antibody, called ____  , and specific treponemal antibodies

reagin

• The ______ tests detect reagin and are only used for screening because this antibody will ____ with similar antigens present in SLE and other autoimmune diseases, pregnancy, and some chronic infections such as hepatitis.

• These conditions can result in biologic _____.

• nontreponemal antigen ; cross-react

• false positives

The percentage of false positives in these tests is high _____ so all reactive results must be confirmed using a test that detects antibodies specifically directed at T. pallidum, the so-called _____

(30–40%), 

treponemal antigen tests

• This test measures the antibody (reagin) a patient has formed against cardiolipin, cholesterol, and lecithin

• Serum samples are diluted to determine an antibody titer

VDRL test

VDRL test

• Tests are read microscopically for ____

• Results are reported as ____ , ____, and ____

• The VDRL test is positive____ weeks after the chancre appears.

• Mainly limited to use on CSF now, this is the only serologic test approved for testing CSF.

• flocculation

• NR (nonreactive), WR (weak reactive), or R (reactive).

• 1–3

is a modified VDRL test

USR test

USR test is a modified VDRL test in which _____ is added to the ____

choline-chloride EDTA ; VDRL Antigen

a. Macroscopic flocculation

b. The assay uses VDRL antigen with charcoal particles

RPR test

RPR test

• The test can be _____ or ____

•  ____ are made to semiquantify the amount of antibody present.

• qualitative or semiquantitative.

• Dilutions

• the most commonly used nontreponemal antigen serologic assay

RPR test

• Treponemal antigen is combined with liposomes.

• If antibodies are present, a mat of agglutination forms in wells of a microtiter plate.

TP-PA test (Fujirebio Inc., Tokyo, Japan)

• An indirect antibody test using the Nichol’s strain of T. pallidum subsp. pallidum affixed into wells of microscope slides

• This test has been replaced by other assays and is no longer recommended by the Centers for Disease Control and Prevention (CDC).

FTA-ABS test