Leishmania donovani is a parasite endemic to parts of India, China, Africa, Southern Europe, South America, and Russia. It has both an amastigote stage inside human cells and a promastigote stage in the gut of sandflies. The life cycle involves transmission between humans and sandflies. In humans it causes visceral leishmaniasis with symptoms like fever, enlarged spleen and liver, and anemia. Diagnosis involves microscopy of tissues or culture. Treatment is with antimony compounds or pentamidine.

1. Leishmania
donovani

2. • Phylum: Sarcomastigophora
• Class: Zoomastigophora
• Genus: Leishmania

3. • Geographical distribution
– Endemic: India, China, Africa, Southern Europe, South
America & Russia
• Habitat
– Parasite of R.E. system
– In the vertebrate host, is always intracellular:
amastigote form

4. • Morphology:
– Amastigote stage (Aflagellar stage): man
– Promastigote form (Flagellar stage): gut of
sandfly & in artificial culture

6. Amastigote stage
• Shape: Round or oval body 2-4 µm
• Cell membrane: delicate
• Nucleus: ‹1 mm in diameter; oval or round
• Kinetoplast comprises of DNA- containing body & a
mitochondrial structure: lies at rt. angle to nucleus
• Axoneme: filament extending from kinetoplast: represents the
root of flagellum

7. Promastigote stage
• Slender spindle shaped body: 15-20µm X 1-2
µm
• Nucleus: central
• Flagellum projects from the front

8. • Reservoir of infection: dog; man
• Transmission: sandfly of genera Phlebotomus &
Lutzomyia

9. Life cycle

10. • Man
– Amastigote form: multiplies by binary fission; host cell enlarged :
becomes packed by parasites, eventually ruptures
– Parasite again taken up by fresh cells & the cycle is repeated
– Some free amastigotes phagocytosed by neutrophilic granulocytes &
monocytes (macrophages)
• Sandfly draws these free amastigote form a.w.a those within
monocytes during its blood meal
Life cycle

11. • Sandfly
– Amastigote forms develop into promastigote form: multiply by
binary fission in the mid gut of sandfly
– The flagellates then spreads to anterior part of alimentary canal
(pharynx & buccal cavity)
– Heavy pharyngeal infection observed b/w 6-9th day after blood
meal (anterior station infection)
– Bite of sandfly: infection

13. • Incubation period: 3-6 months
• Clinical features
– Pyrexia: double rise in 24 hrs
– Splenic enlargement
– Liver enlarged
– Epistaxis
– Skin dry,rough & pigmented
– Jaundice
– Anemia

14. Diagnosis
• Direct evidences
– Microscopy
• Splenic pulp tissue
• Bone marrow
• Blood
• Lymph node: aspirate or biopsy

15. – Culture
• 1-2 ml of blood taken aseptically from a vein: diluted
with 10ml citrated saline solution
• Cells allowed to settle in a cool incubator (22˚C)
• Cellular deposits inoculated in the water of
condensation of N.N.N medium (Novy, MacNeal,
Nicolle ) : incubated at 22˚C for 1-4 weeks

16. Serological test
• DAT
• RK-39 test

17. • Indirect evidences
– Blood count: neutropenia, relative increase of lymphocytes
& monocytes
– Serological tests: Aldehyde test: for rise of gamma globulin
– Antimony tests
– Complement fixation tests with W.K.K. antigen

18. • Leishmanin test
• Adler’s test

19. Treatment
• Antimony compounds
• Pentamidine isethionate

20. Prophylaxis
• Attack on parasite
• Attack on vector
• Personal prophylaxis

21. Post kala azar dermal
leishmaniasis
• Depigmented macules
• Erythematous patches
• Yellowish pink nodules