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Laboratory Diagnosis

  • T. b. rhodesiense trypomastigote stage can be found easily is blood
    • Numbers of parasites are usually numerous
    • Can be found in a biopsy of the chancre or in lymph nodes also
    • Giemsa stained smears or wet preps
    • See http://youtu.be/EnsydwITLYk to observe motile trypomastigotes
  • T. b. gambiense is found usually by microscopic examination of a posterior cervical lymph node aspirate
    • Difficult to detect in blood
    • Concentration techniques and serial examinations are frequently needed
    • Examination of the buffy coat
    • Mini anion-exchange/centrifugation
  • Meningoencephalitic stage involves obsevation of trypanosomes in CSF
    • CSF WBC count of 5 per mm3 or greated
    • Elevated CSF protein
  • Morphology
    • Centrally located nucleus
    • Undulating membrane
    • Anterior flagellum
    • Small posterior kinetoplast
    • Length of 14-33 µm
  • CDC/ Blaine Mathison


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