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Leishmaniasis Leishmania donovani (complex) (VL) Leishmania tropica (CL) Leishmania major (CL) Leishmania aethiopica (CL) Leishmania mexicana (Complex) (CL) Leishmania brazilliensis (complex) (MCL) Leishmania peruriana


The Parasite •

Phylum

Sarcomastigophora

Order

Kinetoplastida

Family

Trypanosomatidae

Genus

Leishmania


Morphology Digenetic Life Cycle •

Promasitogte • Insect • Motile • Midgut

Amastigote • Mammalian stage • Non-motile • Intracellular


Morphology •

Promastigote

•

Flagella Kinetoplast Golgi Nucleus Cytoskeleton

Amastigote


Promastigote


•

Amastigotes (*) of Leishmania donovani in the cells of a spleen. The individual amastigotes measure approximately 1 Âľm in diameter.


Amastigote


•

Amastigotes of Leishmania in a macrophage from a lymph node of a dog.


•

Leishmania (LeishmanDonovan or LD bodies). Lying in macrophage cells from liver. Giemsa. Ă—12000. Enlarged by 9.6.


•

A macrophage filled with Leishmania amastigotes.

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Life cycle •

The organism is transmitted by the bite of several species of blood-feeding sand flies (Phlebotomus) which carries the promastigote in the anterior gut and pharynx. It gains access to mononuclear phagocytes where it transform into amastogotes and divides until the infected cell ruptures. The released organisms infect other cells. The sandfly acquires the organisms during the blood meal, the amastigotes transform into flagellate promastigotes and multiply in the gut until the anterior gut and pharynx are packed. Dogs and rodents are common reservoirs.

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Mammalian Hosts • • • • • •

Rodents Gerbils Hyraxes Bats Porcupines Opossums

• • • • • •

Sloths Primates Dogs Foxes Anteaters .....

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Vectors Phlebotomine Sandflies 6 genera world wide distribution Phlebotomus & Lutzomia 500 species Females Haematophagus Males sap feeders

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Clinical Disease •

Visceral • Fatal (90% untreated) • Liver • Spleen • Bone marrow

Cutaneous • Generally Self- healing • Skin • Mucous membranes

SPECTRUM OF DISEASE

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Initial Infection • • • •

Similar in all species Inoculation of promastigotes Inflammation & chemotaxis Receptor mediated phagocytosis

Promastigote

Amasitgote Transformation

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Parasite Spread Macrophage lysis & parasite release Lymphatic spread Blood spread Target organs Skin/lymph nodes/spleen/liver/ bone marrow

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Visceral Leishmaniasis • • •

1903 1920 1931

William Leishman Pentavalent antimony Experimental transmission

Leishmania donovani (Complex) L.d. archibaldi - L.d.chagasi - L.d.donovani - Ld.infantum

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VL - Clinical Manifestation Variable - Incubation 3-100+ weeks Lowgrade fever Hepato-splenomegaly Bone marrow hyperplasia Anemia, Leucopenia & Cachexia Hypergammaglobulinnemia Epistaxis , Proteinuria, Hematuria

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•

Profile view of a teenage boy suffering from visceral leishmaniasis. The boy exhibits splenomegaly, distended abdomen and severe muscle wasting.

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•

A 12-year-old boy suffering from visceral leishmaniasis. The boy exhibits splenomegaly and severe muscle wasting.

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Jaundiced hands of a visceral leishmaniasis patient.

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Enlarged spleen and liver in an autopsy of an infant dying of visceral leishmaniasis.

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Post Kala Azar Dermal Leishmanoid Normally develops <2 years after recovery Recrudescence Restricted to skin Rare but varies geographically

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Cutaneous leishmaniasis of the face.Â

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A cutaneous leishmaniasis lesion on the arm.

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INFECTION Sub-clinical or inapparent infection

Recovery Immune to reinfection PKDL

Death Concurrent infection

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Diagnosis Clinical signs & symptoms Hypergammaglobulinemia ELISA/Formol gel

Bone marrow biopsy Spleen or liver biopsy Culture & Histology

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Speciation • • • •

Similar morphology Isoenzyme profiles - Zymodemes Monoclonal antibodies DNA hybridisation - PCR

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Treatment Good nursing Diet Antibiotics Pentavalent antimony Pentamidine New drugs - New delivery

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Control • • • •

Vector control Reservoir control Treatment of active cases Vaccination

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Leishmania  
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