SEROLOGY OF SYPHILIS
Assist Prof Dr.
Syed Yousaf Kazmi
SEROLOGY OF SYPHILIS
OBJECTIVES
• Perform Rapid Plasma Reagin Test
• Understand the principle of screening test of
syphilis
• Learn different conditions giving rise to false
positive serology of screening test of syphilis
• Interpret results of screening test in different
SYPHILIS INTRODUCTION
• The name "syphilis" was
coined by Italian physician
and poet Girolamo Fracastoro
in his Latin written poem
“Syphilis sive morbus gallicus”
("Syphilis or The French
Disease") in 1530
• The genus name, Treponema,
is derived from the Greek
term for "turning thread“
• One of the oldest disease
known to mankind
SYPHILIS INTRODUCTION
• Genus Treponema include
– Treponema pallidum subspp pallidum (syphilis)
– Treponema pallidum subspp pertenue (yaws)
– Treponema pallidum subspp endemicum (bejel)
– Treponema carateum (pinta)
All subspp are indistinguishable serologically from
each other
SYPHILIS INTRODUCTION
• Highly contagious
• Penetrate unbroken skin/
through abrasions
• Never been cultured on
artificial media/ tissue
culture
• Only human host
• Organism survives 4oC
temp for 24 hoursimportant for blood
transfusion
SYPHILIS INTRODUCTION
A. ACQUIRED SYPHILIS



Primary syphilis
Secondary syphilis
Latent syphilis


Early latent
Late latent

Tertiary syphilis

Yaws, Pinta, Bejel
B. CONGENITAL SYPHILIS
C. SYPHILIS RELATED DISEASE
Yaws
PRIMARY SYPHILIS
• IP: 9-90 days, usually ~21 days.
• Develops at site of
contact/inoculation.
• Classically: single, painless,
clean-based, indurated ulcer,
with firm, raised borders
• Mostly ano-genital, but may
occur at any site (tongue,
pharynx, lips, fingers, nipples,
etc...)
• Non-tender regional adenopathy
• Very infectious
SECONDARY SYPHILIS
• 6 wks to 6 months after
primary chancre
• Diffuse non-pruritic
indurated rash on body
including palms & soles.
• Fever, malaise, headache,
sore throat
• Highly infectious
LATENT SYPHILIS
• Positive syphilis serology
without clinical signs of
syphilis
• begins with the end of
secondary syphilis and
may last for a lifetime
• Early(infectious) and late
phase(Non-infectious)
• Untreated syphilis
– 30% cure
– 30% latent
– 30% tertiary phase
TERTIARY SYPHILIS
• Years/ decades later
• Granulomatous lesion
called Gumma
• Skin, bones, liver
• Destructive lesions in
CNS-stroke, paresis, tabes,
neuropsychiatric
symptoms etc.)
• CVS-Aortitis, aneurysm,
valvular insufficiency
• Non infectious
SEROLOGICAL TESTS
• Non Treponemal Tests
– VDRL, RPR
– Treponemal infection induce formation of two types
of antibodies
• Reagin (that react with non-treponemal Cardiolipin)
• Specific anti-treponemal antibodies
• Treponemal Tests
–
–
–
–
TP-PA (Treponema pallidum particle agglutination)
TPHA (Treponema pallidum heam-agglutination)
ELISA
FTA-ADS test
NON-TREPONEMAL SCREENING
TESTS
Widely available
Cheap
Easy to perform
Rapid results in minutes
Correlate with disease activity (become
negative with successful treatment)
• False positivity-Preg, autoimmune dis, EBV inf,
• May be false negative in early Prim syphilis
•
•
•
•
•
NON-TREPONEMAL SCREENING
TESTS
• Rapid Plasma Reagin test
• Cardiolipin-cholesterollecithin acts as antigen
• Reagins are mixture of
IgG/IgM
• Colored compound is
attached with antigen
• Visible clumping occurs in
minutes
• Antigen antibody complex
visible on card
RPR TEST
RPR TEST
Positive 2-3 weeks in Prim untreated Syphilis
Highly positive in secondary syphilis
Becomes negative 6-8 months after treatment
Quantitative test- response to therapy
Positive RPR late after therapy means ineffective
treatment/ re-infection
• False positivity in viral infections (infectious
mononucleosis), bacterial infections (e.g.,
pneumonia, TB), chronic disease (e.g., RA, SLE),
elderly, Pregnancy
•
•
•
•
•
TREPONEMAL TESTS
• Use Treponema pallidum
antigen
• Detects specific antiTreponemal antibodies
• Specific tests for syphilis
• Once positive-remain
positive for life
• Do not revert to negative
with treatment
• Expensive
• Laborious, time
consuming
• Expertise req
INTERPRETATION OF SEROLOGICAL
TESTS FOR SYPHILIS
NonTreponemal
tests
(RPR/ VDRL)
+
Treponemal
Tests
(TP-PA/
FTA-ADS)
+
+
–
–
+
–
–
Possible Explanation
Syphilis - recent or previous
Yaws or pinta
No syphilis
False positive
Consistent with previously treated or
untreated Syphilis
Yaws, Pinta, Bejel
No syphilis
Syphilis in incubation period