Leishmania

1. 1
Leishmaniasis
Leishmania donovani (complex) (VL)
Leishmania tropica (CL)
Leishmania major (CL)
Leishmania aethiopica (CL)
Leishmania mexicana (Complex) (CL)
Leishmania brazilliensis (complex) (MCL)
Leishmania peruriana

2. 2
The Parasite
• Phylum
• Order
• Family
• Genus
Sarcomastigophora
Kinetoplastida
Trypanosomatidae
Leishmania

3. 3
Morphology
• Promasitogte
• Insect
• Motile
• Midgut
• Amastigote
• Mammalian stage
• Non-motile
• Intracellular
Digenetic Life Cycle

4. 4
Morphology
• Promastigote • Amastigote
Flagella
Kinetoplast
Golgi
Nucleus
Cytoskeleton

5. 5
Promastigote

6. 6
• Amastigotes (*)
of Leishmania
donovani in the
cells of a
spleen. The
individual
amastigotes
measure
approximately 1
µm in
diameter.

7. 7
Amastigote

8. 8
• Amastigotes of
Leishmania in a
macrophage from
a lymph node of
a dog.

9. 9
• Leishmania
(Leishman-
Donovan or LD
bodies). Lying in
macrophage cells
from liver. Giemsa.
×12000. Enlarged
by 9.6.

10. 10
• A macrophage
filled with
Leishmania
amastigotes.

11. 11
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.

12. 12

13. 13
Mammalian Hosts
• Rodents
• Gerbils
• Hyraxes
• Bats
• Porcupines
• Opossums
• Sloths
• Primates
• Dogs
• Foxes
• Anteaters
• . . . . .

14. 14
Vectors
Phlebotomine Sandflies
6 genera world wide distribution
Phlebotomus & Lutzomia
500 species
Females Haematophagus
Males sap feeders

15. 15

16. 16
Clinical Disease
• Visceral
• Fatal (90%
untreated)
• Liver
• Spleen
• Bone marrow
• Cutaneous
• Generally Self- healing
• Skin
• Mucous membranes
SPECTRUM OF DISEASE

17. 17
Initial Infection
• Similar in all species
• Inoculation of promastigotes
• Inflammation & chemotaxis
• Receptor mediated phagocytosis
Promastigote Amasitgote
Transformation

18. 18
Parasite Spread
Macrophage lysis & parasite release
Lymphatic spread
Blood spread
Target organs
Skin/lymph nodes/spleen/liver/
bone marrow

19. 19
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

20. 20
VL - Clinical Manifestation
Variable - Incubation 3-100+ weeks
Lowgrade fever
Hepato-splenomegaly
Bone marrow hyperplasia
Anemia, Leucopenia & Cachexia
Hypergammaglobulinnemia
Epistaxis , Proteinuria, Hematuria

21. 21
• Profile view of a
teenage boy suffering
from visceral
leishmaniasis. The boy
exhibits splenomegaly,
distended abdomen
and severe muscle
wasting.

22. 22
• A 12-year-old boy
suffering from visceral
leishmaniasis. The
boy exhibits
splenomegaly and
severe muscle
wasting.

23. 23
• Jaundiced hands of
a visceral
leishmaniasis
patient.

24. 24
• Enlarged spleen and
liver in an autopsy of
an infant dying of
visceral leishmaniasis.

25. 25
Post Kala Azar Dermal
Leishmanoid
Normally develops <2 years after
recovery
Recrudescence
Restricted to skin
Rare but varies geographically

26. 26
Cutaneous leishmaniasis of
the face.

27. 27
A cutaneous leishmaniasis
lesion on the arm.

28. 28
INFECTION
Sub-clinical or inapparent infection
Recovery Death
Immune to reinfection Concurrent infection
PKDL

29. 29
Diagnosis
Clinical signs & symptoms
Hypergammaglobulinemia
ELISA/Formol gel
Bone marrow biopsy
Spleen or liver biopsy
Culture & Histology

30. 30
Speciation
• Similar morphology
• Isoenzyme profiles - Zymodemes
• Monoclonal antibodies
• DNA hybridisation - PCR

31. 31
Treatment
Good nursing
Diet
Antibiotics
Pentavalent antimony
Pentamidine
New drugs - New delivery

32. 32
Control
• Vector control
• Reservoir control
• Treatment of active cases
• Vaccination