Medical Parasitology Lab

Blood Flagellates:    

Trypanosoma brucei gambiense Trypanosoma brucei rhodesiense Trypanosoma cruzi Leishmania spp.

Blood and tissue parasites: Toxoplasma gondii

Trypanosoma b. gambiense &T. b. rhodesiense Life cycle

Trypanosoma b.gambiense &T.b.rhodesiense Life cycle

Trypanosoma b.gambiense &T.b.rhodesiense Thin blood film containing Trypomastigote stage: “S” shape  Have small Kinetoplast near blunted, posterior end .  Conspicuous undulating membrane with flagellum.  One nucleus  This is Dividing stage in definitive host. ----------------------------------------------- Infective stage: Trypomastigote Disease: African trypanosomiasis or sleeping sickness. Vector: Glossina spp. ( Tsetse fly) Drug of choice: Melarsoprol, Suramin, Pentamidine, Eflornithin. 

Trypanosoma cruzi life cycle

Trypanosoma cruzi

Trypanosoma cruzi Thin blood film containing Trypomastigote stage: Size range: 12-35 um long by 2-4 um wide.  Shape: “C” or ”U” in stained blood films.  Appearance: Long and slender  Nucleus: One, located anterior to the kinetoplast.  Large Kinetoplast near the pointed posterior end.  Inconspicuous undulating membrane. ---------------------------------------------- Infective stage: Trypomastigote  Vector: Triatoma spp. (Triatomid bug).  Disease: American Trypanosomiasis ( chagas’ disease).

Trypanosoma cruzi Amastigotes in stained rat skeletal muscle section: Intracellular Amastigotes. Size range: 3 by 5 um.  Shape: Round to oval  Nucleus: One, usually off center.  Other feature: Present Kinetoplast This is the dividing stage in host. ---------------------------------------------- Infective stage: Trypomastigote  Vector: Triatoma spp. ( Triatomid bug).  Disease: American Trypanosomiasis (chagas’ disease). 

Trypanosoma cruzi 

Epimastigotes in culture:

Size range: 9-15 um Appearance: Long and slightly wider than promastigote form. Nucleus: One, located in posterior end. Other features: Kinetoplast located anterior to the nucleus. Undulating membrane: Extending to the half of body length. Free flagellum, extending from anterior end.

Leishmania sp. Leishmania tropica ( causes cutaneous leishmaniasis ).  Leishmania braziliensis ( causes mucocutaneous leishmaniasis).  Leishmania donovani ( causes visceral leishmaniasis) 

Leishmania sp.

Leishmania tropica Promastigotes Promastigote in culture: Size range: 9-15 um Appearance: Long and slender. Nucleus: One, located in or near center. Other features: Kinetoplast, located in anterior end. Single free flagellum, extending from anterior end. ----------------------------------------------Infective stage: Promastigote Diagnostic stage: Amastigote culture from skin lesion.Immunological techniques. Disease: Cutaneous Leishmaniasis (Also known as Old World leishmaniasis, Oriental sore,and Baghdad or Delhi boil). Vector: Phlebotomus spp. (Sandfly)

Leishmania braziliensis Promastigote

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Skin ulcer smear (Amastigotes):

Size range: 3 by 5 um.  Shape: Round to oval  Nucleus: One, usually off center.  Other feature: Present Kinetoplast ----------------------------------------------Infective stage: Promastigote. Diagnostic stage: Amastigotes in stained Biopsy of the infected ulcer Disease: Mucocutaneous leishmaniasis Vector: Lutzomyia spp. (sandfly). 

Leishmania donovani Amastigotes

Bone Marrow aspirate Showing Amastigotes: Size range: 3 by 5 um.  Shape: Round to oval  Nucleus: One, usually off center.  Other feature: Present Kinetoplast. ----------------------------------------------Infective stage: Promastigote. Diagnostic stage: Amastigotes in stained aspirate of the infected bone marrow. Disease: Visceral leishmaniasis Vector: Phlebotomus spp. (sandfly). 

Toxoplasma gondii  

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Disease: Toxoplasmosis. Location in host: Trophozoite(Tachyzoite)stages are found in various cells, tissues, and fluids. Cyst (Bradyzoite) stages occur in the central nervous system, as well as in the skeletal and cardiac muscles and other visceral organs. Definitive host : Cats Intermediate host: mice, rats, and accidentally humans. Infective stage: Oocyst Diagnostic stage: Based mainly on symptoms and use of serological techniques.

Toxoplasma gondii life cycle1

Toxoplasma gondii life cycle2

Toxoplasma gondii Bradyzoites 

Mouse brain sections show Bradyzoites cyst:

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General comment: Slowgrowing morphological form.

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Size: Smaller than tachyzoites.

Other feature: Hundreds to thousands of bradyzoites enclose themselves to form a cyst that may measures 12-100 um in diameter.

Toxoplasma gondii Tachyzoites 

Slide shows infected Peritoneal fluid of mouse

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General comment: Actively

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multiplying morphologic form. Size : 3-7 um by 2-4 um Shape: Crescent shaped, often more rounded on one end and tapered from another end. No. of nuclei: One No Kinetoplast in this parasite.