Parasites 2 Flashcards
Leishmania donovani - Geographic Distribution
China, India, Middle East, Africa, Latin America.
Leishmania donovani - Morphology
Amastigote: Small (round, ~1.5 µm), large nucleus, rod-shaped kinetoplast, short internal flagellum.
Promastigote: Elongated, large nucleus, anterior kinetoplast, long free flagellum.
Leishmania donovani - Life Cycle
Amastigotes multiply in the reticuloendothelial system (spleen, liver, bone marrow).
Sandfly ingests amastigotes, which transform into promastigotes in the sandfly’s gut. Promastigotes multiply and are injected into humans during feeding, transforming into amastigotes in macrophages.
Leishmania donovani - Diagnostics
Demonstration of Leishman-Donovan bodies in spleen, liver, bone marrow.
Giemsa stain of smears.
Culture in special media.
PCR and serological tests also used.
Leishmania donovani - Pathogenicity
Visceral leishmaniasis (kala-azar):
Affects spleen, liver, bone marrow. Leads to anemia, hepatosplenomegaly, bone marrow suppression, hyperglobulinemia, and wasting.
Leishmania braziliensis - Geographic Distribution
Central and South America (Brazil, Peru, etc.)
Leishmania braziliensis - Morphology
Amastigote: Small, ovoid, large nucleus, kinetoplast.
Promastigote: Elongated, large nucleus, anterior kinetoplast, long flagellum.
Leishmania braziliensis - Life Cycle
Amastigotes multiply in the mucosal tissues.
Promastigotes develop in sandflies and are transmitted during feeding.
Leishmania braziliensis - Diagnostics
Biopsy of mucosal tissue or skin.
PCR for species identification.
Serological tests may be used, but biopsy of mucosal lesions is definitive.
Leishmania braziliensis - Pathogenicity
Mucocutaneous leishmaniasis:
Destroys mucosal tissues (nose, mouth), leading to disfigurement and secondary infections.
Leishmania tropica - Geographic Distribution
Urban areas of Mediterranean, Soviet Union (Armenia, Azerbaijan, etc.), Afghanistan, India, Turkey.
Leishmania tropica - Morphology
Morphology is identical to L. donovani:
Amastigote: Small, ovoid, large nucleus, rod-shaped kinetoplast.
Promastigote: Elongated, large nucleus, anterior kinetoplast, long flagellum.
Leishmania tropica - Life Cycle
Amastigotes multiply in macrophages and live within tissues. Transmitted by sandflies. Amastigotes remain in infected tissues, causing cutaneous lesions, which may leave scars when healed.
Leishmania tropica - Diagnostics
Microscopic examination of material from the edge of ulcerated lesion may reveal parasites.
Culture of skin scrapings.
PCR may confirm species.
Leishmania tropica - Pathogenicity
Cutaneous leishmaniasis (Oriental sore, Aleppo button):
Characterized by skin ulcers, which may leave scars after healing. In some cases, ulcers may become secondarily infected.
Toxoplasma gondii - Geographic Distribution
Worldwide