SYPHILIS

Introduction

Syphilis is a curable sexually transmitted disease (STD) caused by spirochete Treponema pallidum. Transmission of the organism occurs during vaginal, anal or oral sex. Pregnant women with the disease can pass it to the babies they are carrying.

The natural course of disease is arbitrarily divided into three stages: After an incubation period of about three weeks, a primary non-painful skin lesion (sore) appears and is often associated with regional lymphadenopathy. A secondary bacteremic or disseminated stage is associated with generalized mucocutaneous lesions and generalized lymphadenopathy. This stage is followed by a latent period of sub-clinical infection (latent syphilis) lasting many years and is only diagnosed by serologic tests.

Syphilis is passed from person to person through direct contact with syphilis sore. Sore occurs mainly on the external genitals, vagina, anus or in the rectum.

Having had syphilis does not protect from getting it again.

It is now known that the genital sores caused by the syphilis also make it easier to transmit and acquiring HIV infection sexually. The individual with syphilis have increased risk of acquiring HIV infection.

T. pallidum cannot be cultivated In-Vitro.

Diagnosis

  • Physical examination: Clinical evidences of infection around sexual organs.
  • Microscopic examination (Dark-field microscopy): Most reliable method but needs specimen from syphilis lesions (sores).
  • Serological examinations: Detection of antibodies of Treponema pallidum or reagin antibodies.

Following assays are commercially available for syphilis antibody diagnosis.

  • VDRL tests: Detects reagin antibody : Not specific test.
  • RPR tests: Detects reagin antibody : Not specific test.
  • Fluorescent treponemal antibody absorption test (FTA_ABS)
  • Treponema-pallidum hemagglutination test (TPHA)
  • Treponema-pallidum immobilization test (TPI)

Limitations of the existing diagnostic methods

Microscopic Test

  • Specimen from infected lesions required.
  • An experienced and qualified technical expert required

VDRL/RPR test

  • Detects reagin antibodies which are not directed against Treponema-pallidum.
  • Test is not specific for Syphilis diagnosis and these reagin antibodies develops in other infections also.
  • The cross reaction of antigen used in these tests with other diseased status. Non Treponemal antigen (cardiolipin) used in the reagent formulation.

TPHA test

  • The reliable and confirmatory test for Syphilis diagnosis but time consuming and needs the expert technical staff.
  • Per test cost is high.
  • Needs storage in refrigerator.

NANO SYPHILIS TEST

Nano Syphilis Test is a qualitative, single step, lateral flow , ready to use rapid card test for detection of Treponema-pallidum antibodies in human serum or plasma.

  • It is more Specific and Sensitive test than routinely used RPR, VDRL tests for diagnosis of syphilis. No cross reaction with other antibodies.
  • It has very specific cocktail of recombinant antigen immobilized on test strip to capture the Treponema pallidum.capture the Treponema pallidum.
  • No heat inactivation or dilution of the specimen required to perform the test. Just add required drops of the serum or plasma in sample well and read result within 5 to 20 minutes of sample addition.
  • Visual interpretation of the result in form of pink / purple line.
  • No instrumentation and technical expertise required.
  • It is individually packed ready to use test device having no buffer.
  • Results within 5 to 20 minutes.
  • Best alternative to TPHA assay for confirmation of Syphilis antibody.

Test Procedure

  • Take the test device and place it on flat surface.
  • Add 2 drops of serum/plasma using dropper provided with the test.
  • Read result within 5-20 minutes. DO NOT INTERPRET AFTER 20 MINUTES

Interpretation

Positive: Appearance of two pink/purple lines one each at control (C) and one at test (T) zone indicates that sample is positive for Treponema pallidum antibodies.

Negative: Only one line at the control zone indicates that sample is negative for for Treponema pallidum antibodies.

Invalid: If control line does not appears at the 'C' or if both test and control lines does not appears, the test is invalid and should be repeated.

 

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