Part 1

• Treponema are unicellular organisms that are slender, helically coiled, flexible organisms, motile, resulting from the action of axial filaments which are also responsible for its spiral shape.
• Treponema are facultative anaerobes and multiply by transverse fission.
• The word Treponema is derived from a Greek word meaning “turning thread” and they are corkscrew-like organisms.
• The spirals of Treponema are so thin that they are not readily seen unless darkfield illumination or immunofluorescent stain is employed.
• Treponema are not stained very well with aniline dyes, but they do reduce silver nitrate to metallic silver that is deposited on the surface so the treponemes can be seen in tissues (Levaditi Silver Impregnation).
• Pathogenic strains of Treponema have never been cultured with certainty on artificial media, in fertile eggs, or in tissue culture but maintained in the testicular chancres of rabbits.
• Non-pathogenic strains (Reiter strain) can be cultured anaerobically in vitro and grows on a defined medium of amino acids, vitamins, salts, minerals and serum albumin.
• Treponema remain viable in whole blood or plasma for at least 24 hours which is of potential importance in blood infusion.
• Treponema are killed rapidly at 42 o C and is used as a basis for syphilis therapy.
• A life cycle has been postulated from Treponema pallidium consisting of granular stage, cyst-like spherical bodies and spirochetal form.
• There are two types of antibodies produced: reagin, an antibody like substance and antitreponemal antibody, a true antibody, both of which can be used for the serologic diagnosis of syphilis.
• Acquired Syphilis is classified into stages: Primary stage, Secondary stage, and Latent stage.
• Primary stage of Acquired Syphilis is characterized by the appearance of hard chancre or hunterian chancre in the genitalia, which appears after 10 days to several months incubation period.
• During the Primary stage of Acquired Syphilis, Dark field microscopy, special stains such as Levaditi Silver Impregnation, Fontana Tribondeau (gold in color), and Serological tests are used for laboratory diagnosis.
• Secondary stage of Acquired Syphilis is characterized by the appearance of condylomata lata all over the body, which appears 6 – 8 weeks after the appearance of initial chancre.
• Treponema Pallidium Immobilization uses live and motile treponemes, patient’s serum, and complement; if immobilized, the patient’s serum contains specific treponemal antibodies.
• Treponema Perteneue is the causative agent of Yaws or Frambresia which is a disease of bone and skin; a non-venereal disease and transmitted to man through direct contact or through the aid of flies.
• Microagglutination Assay for Treponema pallidium antibodies (MHA – TPA) is based upon agglutination by specific antibodies in serum with lyophilized, formalinized, tanned sheep RBC sensitized with Treponema pallidium antigen.
• Primary lesion or Mother Yaws or Framboise is the initial lesion which develops 3 – 4 weeks after exposure.
• Fluorescent Treponema Antibody Test (FTA) is used to diagnose syphilis.
• Treponemal Antibody Test detects organisms containing antigen.
• Jerisch – Herxheimer reaction is a reaction most commonly observed in the early stages of syphilis when treated after 2 – 12 hours with either heavy metals of penicillin; commonly observed reactions are headache, malaise and a temperature above 38 o C.
• Congenital Syphillis is the transmission of the disease from syphilitic mother to the fetus through the placenta; some of the fetus may die, others are still born alive.
• Fluorescent Treponema Antibody – Absorption (FTA – ABS) is the most specific test for syphilis; a modification of FTA which uses as antigen a killed suspension of Treponema pallidium obtained from infected rabbits.
• Fluorescent Antibody Test (FAT) is used to confirm the validity of (+) reagin test and is also used to diagnose congenital syphilis and the late stages of syphilis.
• Rapid Plasma Reagin (RPR) uses unheated serum which is added to RPR antigen; performed on a white, plastic coated card.
• Tertiary stage of syphilis takes place when the latent stage is not treated; involvement of the deep organs of the disease (cardiac syphilis, neurosyphilis) known as gummas.
• Complement Fixation Test Wasserman Kolmer is used to detect syphilis.
• Flocculation Test (a) Venereal Disease Research Laboratories (VDRL) uses heat inactivated serum which is added to antigen.
• Reiter Protein Complement Fixation uses an extract from non-virulent treponemes as antigen; non-reactive in the late stages of syphilis.
• Other spirochetes include Spirillum minor which causes rat bite fever known as sodoku, Spirillum volutans, Magneto tacticum, and Azospirillum.
• Serologic tests like VDRL, CF and use of Proteus OXK are used in the serologic test for Leptospira.
• The only spirochete found in the peripheral blood stained by direct stain in which the finding of stained spirochetes is sufficient to establish a definitive diagnosis of relapsing fever is Borrelia burgdorferi.
• Culture using Kelly media A and chick embryo is a method of laboratory diagnosis of spirochetes.
• Leptospira interrogans is found in proximal tubules of kidneys of infected animals and is passed in human, human infection results from contact with animal urine or water which has been contaminated with urine like soil, natural water (flood), foodstuff.
• Leptospirosis develops after an incubation period of 10 – 12 days, the signs and symptoms vary from a mild fever to severe illness including jaundice, kidney failure and meningitis.
• Culture using Fletcher’s medium, which contains frozen dried serum with hemoglobin, is a method of laboratory diagnosis of Leptospira.
• Darkfield microscopy and animal inoculation test are methods of laboratory diagnosis of Leptospira.
• Animal inoculation using white mice is a method of laboratory diagnosis of spirochetes.
• Borrelia buccalis is a spirochete which occurs in every normal mouth.