Leishmaniasis David P. Humber Department of Life Sciences University of East London

Lecture Topics The parasite and vector The life-cycle Clinical features Diagnosis Epidemiology Chemotherapy Vaccination

Introduction Leishmaniasis Protozoal disease of mammals Largely zoonotic 23+ pathogenic species Cutaneous leishmaniasis Visceral Leishmaniasis

The Parasite Phylum Order Family Genus Sarcomastigophora Kinetoplastida Trypanosomatidae Leishmania

Morphology Promasitogte –Insect –Motile –Midgut Amastigote –Mammalian stage –Non-motile –Intracellular Digenetic Life Cycle

Morphology PromastigoteAmastigote Flagella Kinetoplast Golgi Nucleus Cytoskeleton

Scanning EM of Promastigote Rosette

Promastigote in Culture Kinetoplast Nucleus

Scanning EM TIA

Amastigotes - skin biopsy

Speciation Similar morphology DNA bouyant density Isoenzyme profiles - Zymodemes Monoclonal antibodies DNA hybridisation - PCR

Species Pathogenic in Humans Leishmania aethiopica Leishmania brazilliensis (complex) Leishmania donovani (complex) Leishmania major Leishmania mexicana (complex) Leishmania tropica

Mammalian Hosts Rodents Gerbils Hyraxes Bats Porcupines Opossums Sloths Primates Dogs Foxes Anteaters.....

Canine Host

Procavia capensis

Sloth Host

Distribution of Leishmaniasis

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

Sandfly - Phlebotomous pedifer

Clinical Disease Visceral –Fatal (90% untreated) –Liver –Spleen –Bone marrow Cutaneous –Generally Self- healing –Skin –Mucous membranes SPECTRUM OF DISEASE

Initial Infection Similar in all species Inoculation of promastigotes Inflammation & chemotaxis Receptor mediated phagocytosis Promastigote Amasitgote Transformation

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

Visceral Leishmaniasis William Leishman Pentavalent antimony Experimental transmission Leishmania donovani (complex) L.d. archibaldi - L.d.chagasi L.d.donovani - Ld.infantum

VL - Clinical Symptoms Variable - Incubation weeks Lowgrade fever Hepato-splenomegaly Bone marrow hyperplasia Leucopenia & Cachexia Hypergammaglobulinnemia

Visceral Leishmaniasis

Epidemiology - Distribution

INFECTION Sub-clinical or inapparent infection Recovery Death Immune to reinfection Concurrent infection PKDL

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

Diagnosis Clinical signs & symptoms Hypergammaglobulinemia ELISA/Formol gel Bone marrow biopsy Spleen or liver biopsy Culture & Histology

Biopsy punch

Specificity of L. aethiopica primers Marker L.. aethiopica L. tropica L. major L.. donovani

Treatment Good nursing & Diet Antibiotics Pentavalent antimony (upto 25% ressistance) Pentamidine Amidosidine New drugs - New delivery

Immune Response Innate IRs –Lsh/BCG gene Lsh r Lsh s –No real human equivalent –Other species specific genes described –Complement –Polymorphs –Macrphages

Macrophages Receptors –CR3 receptors for C3bi –Lipophosphoglycan –GP63 Killing Oxygen dependent Oxygen independent

Macrophage activation T cell activation –TH - 1 IL2, Gamma interferon –TH - 2 IL4, IL5 SALT –Langerhans cells –Tissue dendritic cells

Vaccines Leishmania + BCG –Ecuador - 3 species (Lbb,Lbg,Lma) 2 doses killed whole parasites 70% protection –Iran - 1 species (Lt) 1 dose whole killed 35% responded 0% cf BCG alone

CL - Cutaneous Leishmaniasis Old World –Leishmania aethiopica –Leishmania major –Leishmania tropica New World –Leishmania brazillensis L.b. –Leishmania mexicana L.m Spectrum LCL - MCL - DCL

Localised Cutaneous Leishmaniasis Single or multiple lesions –Usually on head and/or neck Generally self-healing –Variable few week to many months Ulceration followed by healing & scar –Secondary infection & tissue erosion

Localised Cutaneous Leishmaniasis

Mucocutaneous Leishmaniasis Direct inoculation or extension –L.aethiopica & others –Low cell mediated immunity (CMI) Metastatic spread –L.b.brazilliensis –High CMI & extensive tissue destruction –Also in DCL but no MI no tissue damage

Mucocutaneous Leishmaniasis

Diffuse Cutaneous Leishmaniasis Multiple diffuse spreading lesions –Usually face & limbs rarely trunk No ulceration Non-healing - life long infection No cell mediated immunity Good antibody response Leishmania aethiopica & Leishmania mexicana mexicana

Diffuse Cutaneous Leishmaniasis

Uta

Epidemiology Old World

Epidemiology New World

Diagnosis Clinical feature & geographical location Skin biopsy/slit skin smear Culture & histology Monoclonal antibodies PCR

Treatment Control secondary infection Self-healing - probably no treatment Surgery/cryosurgery/Topical MCL & DCL Pentavalent antimony - pentamidine

Control Vector control Reservoir control Treatment of active cases Vaccination