HEMOFLAGELLATES

• Hemoflagellates

  Parasites located in blood and tissue that move by means of flagella, belonging to the genera Leishmania and Trypanosoma
• Morphological forms of clinical significance

  • Amastigote
  • Promastigote
  • Epimastigote
  • Trypomastigote
• Amastigote


  • Round to oval, 5 by 3 μm in size, with a nucleus, blepharoplast, and parabasal body
  • Lacks an external flagellum
• Promastigote


  • Long and slender, 9-15 μm in length, with a nucleus in or near the center and a single free flagellum extending from the anterior end
• Epimastigote


  • Long and slightly wider than promastigote, 9-15 μm in length, with a nucleus in the posterior end, an undulating membrane extending half the body length, and a free flagellum extending from the anterior end
• Trypomastigote


  • Long and slender, 12-35 μm long by 2-4 μm wide, often C, S or U shaped, with a posteriorly located kinetoplast, an anterior nucleus, and an undulating membrane extending the full body length with or without a free flagellum
• Amastigotes are found primarily in tissue and samples, epimastigotes are found primarily in the arthropod vector
• Trypomastigotes reproduce and are visible in the peripheral blood
• Promastigotes may only be seen immediately after transmission into a healthy individual or when cultured
• Specimens for diagnosing hemoflagellates include blood, lymph node and ulcer aspirations, tissue biopsies, bone marrow, and cerebrospinal fluid
• Serologic and molecular tests are also available for confirming the presence of hemoflagellates
• Symptoms of hemoflagellate infections range from minor (skin lesions, fever, diarrhea) to serious (kidney involvement, mental retardation, coma, death)
• Hemoflagellate species known to cause human infections

  • Leishmania braziliensis complex
  • Leishmania donovani complex
  • Leishmania mexicana complex
  • Leishmania tropica complex
  • Trypanosoma brucei gambiense
  • Trypanosoma brucei rhodesiense
  • Trypanosoma cruzi
  • Trypanosoma rangeli
• Leishmaniasis has a long history, with depictions on pottery from Ecuador and Peru around the first century AD
• Common names for diseases caused by Leishmania spp.

  • Baghdad boils
  • Bay sore
  • Chiclero ulcer
  • Dum dum fever
  • Espundia
  • Forest yaws
  • Kala-azar
  • Oriental sore
  • Pian bois
  • Uta
• Leishmaniasis


  Caused by Leishmania donovani
• Mucocutaneous leishmaniasis


  Caused by Leishmania braziliensis, the principle cause in Central and South America, particularly in Brazil
• Mucocutaneous leishmaniasis


  Caused by Leishmania guyanensis, the principle cause in the Guianas, parts of Brazil and Venezuela; also known as pian bois
• Visceral leishmaniasis


  The most severe form, caused by members of the Leishmania donovani complex
• Cutaneous leishmaniasis


  Caused by the infecting agents comprising the Leishmania tropic complex
• Mucocutaneous leishmaniasis

  In the Peruvian Andes
• Leishmania spp. are generally grouped for discussion in one of several ways—in complexes of organisms or taxonomic groupings, their vectors, or the clinical nature of the disease caused
• The four main Leishmania complexes

  • Leishmania braziliensis
  • Leishmania donovani
  • Leishmania mexicana
  • Leishmania tropica
• Leishmania braziliensis complex


  Found in Mexico, Argentina, Panama, Colombia, the Peruvian Andes, Guiana, Brazil, Bolivia, Paraguay, Ecuador, and Venezuela
• Organisms in the Leishmania braziliensis complex

  • Leishmania braziliensis
  • Leishmania panamensis
  • Leishmania peruviana
  • Leishmania guyanensis
• Specimen of choice for identifying Leishmania braziliensis complex

  Biopsy of the infected ulcer
• Diagnostic methods for Leishmania braziliensis complex

  1. Microscopic examination of Giemsa-stained preparations

  2. Culturing the infected material

  3. Serologic testing

  4. Restriction analysis of kinetoplast DNA (schizodeme analysis)

  5. Nuclear DNA hybridization

  6. Isoenzyme patterns (zymodeme analysis)
• Vectors for Leishmania braziliensis complex

  Lutzomyia and Psychodopygus sandflies
• Reservoir hosts for Leishmania braziliensis complex

  Dogs and forest rodents
• Mucocutaneous leishmaniasis


  Symptoms typically occur within a few weeks to months after transmission, with large ulcers in the oral or nasal mucosa areas developing
• Treatment for mucocutaneous leishmaniasis caused by Leishmania braziliensis

  Antimony compounds, but resistance has increased<|>Alternative treatments include liposomal amphotericin B and oral antifungal drugs
• Prevention and control for Leishmania braziliensis complex

  Public awareness and education<|>Personal protection against sandfly contact<|>Prompt treatment and eradication of infected ulcers<|>Control of sandfly population and reservoir hosts<|>Vaccine development
• The most commonly used laboratory diagnostic method for the Leishmania braziliensis complex is culturing the infected material
• The organism causing chiclero ulcer is most likely found in the South American rainforest region
• Amoxicillin is not an acceptable treatment for mucocutaneous leishmaniasis caused by Leishmania braziliensis
• Leishmania donovani complex


  Found in India, Pakistan, Thailand, Africa, the Peoples Republic of China, the Mediterranean, Europe, Africa, the Near East, parts of the former Soviet Union, the Middle East, Yemen, Oman, Iraq, Kuwait, Saudi Arabia, United Arab Emirates, Bahrain, and Central and South America
• Organisms in the Leishmania donovani complex

  • Leishmania donovani
  • Leishmania infantum
  • Leishmania chagasi
• Montenegro skin test


  A screening test used for detecting exposure to Leishmania spp.
• Specimen of choice for demonstrating Leishmania donovani complex amastigotes

  Giemsa-stained blood, bone marrow, lymph node aspirates, and biopsies
• Diagnostic methods for Leishmania donovani complex

  1. Giemsa-stained slides

  2. Blood, bone marrow, and tissue cultures

  3. Serologic testing (IFA, ELISA, DAT)

  4. Schizodeme analysis

  5. Zymodeme analysis

  6. Nuclear DNA hybridization