Question

Lab Activity: Testing for Syphilis with the Arlington Scientific (ASI) RPR test kit

1.        Is the prozone effect possible with this assay? At what stage(s) in the disease might this be encountered? How would you go about resolving this issue?

Answer 1

Syphilis is a complex disease in which many organs & tissue of the body can become infected by Treponema pallidum, a spirochete.

This bacterium is thought to enter into the body through very small breaks in the skin or mucous membranes.

It's entry is facilitated by the minor abrasions that often occur during sexual intercourse.

It has variety of signs & symptoms that can mimic a number of other diseases. Consequently compared with other STDs , it is difficult to recognise syphilis. There is association between Syphilis & HIV. Persons with high risk of acquiring syphilis are also at an increased risk of acquiring HIV. If a person with both condition needs more intensive treatment with penciling & should be checked for the involvement of CNS

Clinical Stage	Findings	Communicability	Duration of stage
Primary	Chancre	Highly infectious	3-8 week
Secondary	Cutaneous lesions Prescence of symptoms (malaise, arthralgia headache, liver & kidney dysfunction	Highly infectious	1-2 years
Latent	Abscence of signs & symptoms	Non infectious after 4 years, possible Placental transmission	Through out life / progression to late stage

Late.

Appearance 3-20 years after Infection

Non infectious, spinal fluid possiblycontaining organism

Possibly Fatal &

Nonspecific antitreponemal antibodies can be detected by tests such as the VDRL test & RPR (rapid plasma reagin ) test.

These nontreponemal tests are suitable for screening purpose & usually become positive 10-14 days after the prescence of a chancre.

False negatives & false positive results do occur with VDRL & RPR tests.

A false negative result may be obtained during primary Syphilis, if the test is done before the individual has had time to produce antibodies.

A false positive results may occur with other diseases or condition such as, hepatitis, infrcinfec mononucleosis, after small pox vaccination, Collagen diseases, Pregnancy, Aging

So positive nontreponemal tests results should be confirmed by more specific treponemal tests to rule out other causes

The fluorescent treponemal antibody absorption (FTA-Abs ) test & the T.pallidium particle agglutination ( TP-PA ) test detect specific antitripantitr antibodies & rare suitable for confoconfi the diagnosis.

In the CSF, changes such as increased WBC, total protein & a positive treponemal antibody test are diagnostic of asymptomatic neuro syphilis.