Leishmaniasis
By
Dr. M. Jamjoom
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PROTOZOA
Flagellates
Haemoflagellates
Blood & tissue
Leishmania sp. Trypanosoma sp.
L. tropica complex
T. rhodesiense
L. tropica; L. major; T. gambiense
L. aethiopica T. cruzi
L. donovani complex
L. donovani; L. infantum
(L. chagasi)
L. mexicana complex
L. mexicana
L. braziliensis complex
L. braziliensis
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Hemoflagellates
• Multiply in blood & Tissues.
• Move by flagellum.
• Transmitted by an arthropod (insects)
• Exhibit varying morphology in both
human and an arthropod.
• Multiply by simple binary fission.
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Morphological forms of blood flagellates
Flagellum
Flagellum Undulating
membrane
Kinetoplast Kinetoplast
Nucleus
Nucleus
Amastigote Promastigote Epimastigote Trypomastigote
Morphological stages of the Trypanosomatidae
affecting humans
Leishmania species
Intracellular in
Amastigote
macrophages in
humans
In midgut, then proboscis
Promastigote of sandfly ( infective stage
to human) and in culture
Morphological stages ….cont.
T. rhodesiense
Trypanosoma spp.
T. gambiense
In salivary glands and proboscis of
tsetse fly (transfer stage to human)
Epimastigote
In bloodstream, lymph nodes
Trypomastigote
and later CNS of humans
Morphological stages ….cont.
Trypanosoma cruzi
Intracellular in macrophages
Amastigote
and tissue cells of humans
In midgut, then faeces of
bug (transfer stage to
humans)
Trypomastigote
In blood and tissue spaces of humans
Leishmaniasis
• Obligatory intracellular belong to genus
Leishmania
• It is transmitted by sandflies.
• There is more than 30 species that infect
mammals.
• In human infection caused by about 21 species.
• Zoonotic disease: Infect wild range of animals
act as reservoir hosts (dogs, Rodents…)
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Leishmaniasis
Disease Visceral Cutaneous Muco-cutaneous
(kala azar) (Espundia)
Species L. donovani L. tropica L. braziliensis
L. infantum L. major L. mexicana
L. chagasi L. aethiopica L. amazonensis
L. mexicana
Mexicana
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Leishmaniasis
• Endemic in 88 countries in the tropics and
subtropics
• 350 million people at risk of infection
• Each year overall prevalence of 12 million
cases:
– 0.5 million visceral leishmaniasis
– 10-15 million cutaneous leishmaniasis
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Clinical forms
• The most common clinical forms:
– Cutaneous leishmaniasis (Oriental sore)
– Visceral leishmaniasis (Kala-azar)
– Mucocutaneous leishmaniasis (New World)
(Chiclero’s ulcer; Espundia)
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Morphology
• Life cycle alternating between two
morphologically forms:
– Amastigote (mammalian hosts)
– Promastigote (sandfly vector)
• All species are morphologically similar
• No sexual cycle multiply by binary
fission
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Mode of infection
• Bite of female
sand flies
• Phlebotomine
(in Old World)
• promastigotes
(infective
stage)
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Adult female sandfly biting
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Life cycle of leishmaniasis
Human &reservoir animals Sandfly
Life cycle
alternating
between two
insect
vector &
mammalian
Insect vector
Mammalian hosts
And
Amastigote Promastigote
between two
Pathogenic stage Infective stage
morpholgical
forms
Life cycle
Depending on the
species of
parasite
amastigotes may
In cutaneous leishmaniasis
Amastigotes remain in the
superficial tissues skin
In mucutaneous leishmaniasis
Amastigotes remain in localized to skin plus
spread to mucosae of mouth, nose, larynx,
pharynx, ear
metastases to mucosa
In visceral leishmaniasis
Macrophage infected by Amastigotes multiply
amastigotes spread from in the macrophages of
primary skin lesion via blood organs such as..
Spleen
Liver
Lymph
nodes
Bone
marrow
RE
cells of
GIT
Summary of life cycle in sandfly
Summary of life cycle
• Promastigote form introduced to skin at the
time a sandfly takes a blood meal
• Engulfed by the local macrophages where
transforms into rounded aa
Amastigotes.
• Amastigotes multiply by asexual binary
fission.
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Life cycle cont.
• Amastigotes are released from the ruptured
macrophage aa aa re-initiate replicate
cycles in new macrophages.
• When amastigotes in macrophages are
taken up by another sandfly takes a blood
meal aa aa convert to promastigotes
and undergo binary fission
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Summary of life cycle in sandfly
• Amastigotes ingested by sandfly with a
blood meal
• After 72 hrs, become elongated
(promastigotes) in midgut of sandfly
• Multiply and fill lumen
• After 14-18 days the promastigotes move to
mouth-part
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Visceral leishmaniasis
• Commonly named Kala azar
• Kala-azar in Hindi means black sickness
or black fever
• Other names: Dum-dum fever, and tropical
splenomegaly.
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Visceral leishmaniasis
• 90% of the world's cases of visceral
leishmaniasis are in: India, Bangladesh, Nepal,
Sudan, and Brazil.
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Visceral Leishmniasis
• In old World:
– L. donovani
– L. infantum
(Mediterranean region,
common in children &
young adult)
• In New World:
– L. cruzi
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Mode of infection
Mainly by
Human & Bite of infected
animals Sandfly
Rarely by
Blood transfusion
Congenital
Contaminated
needles
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Clinical symptoms of Visceral
leishmaniasis
• Leishmanioma (At the site of inoculation)
At the site of
inoculation
Leishmanioma
Irregular fever & cont.
Clinical symptoms show 2-3 peaks a day
42
• Irregular fever (may show 2-3 peaks a day)
40
Temperature
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36
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1 2 3 4 5 6 7 8 9 10 11 12 13
Days 29
Clinical symptoms cont.
• Hepatomegaly
• Splenomegaly
• Lymphadenopathy
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Clinical symptoms cont.
• Weight
loss and
wasting
• Jaundice
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Clinical symptoms cont.
• Dark pigmented skin patches
• Oedema
wwHyboalbuminaemia due to liver affection
• Diarrhoea or dysentery
wwMacrophages invasion in the submucosa
causing ulceration
• Haemorrhages bleeding from mucous
membrane (nose, mouth)
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Disease progress may result in
• Sever anaemia
• thrombocytopenia
• Leucopenia
• Sever blood loss
• Infection result in immune suppression
• Secondary infections cause death
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Post kala-azar dermal leishmanoid
• In India and occasionally
east Africa
• Skin reaction (nodules)
• Develops after
incomplete treatment with
antimony
• Nodules contain
parasitized macrophages
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Diagnosis
• Clinical
• Laboratory
– Direct methods:
• Microscopy by
demostration of
parasite from (spleen,
liver, bone marrow or
lymph node)
aspiration and blood
• Suitable culture
media
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Diagnosis
36
Diagnosis
• Indirect methods
– Blood picture
– Intra-dermal test (Leishmanin or Montenegro
test)
– Serological test
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Treatment
• Sodium stibogluconate
(Pentostam)
• Amphotericine B (Fungizone)
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Cutaneous leishmaniasis
• Parasites are mainly found in
reticuloendothelial cells in the skin.
• Life cycles and vectors are similar to those
causing visceral leishmaniasis.
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Cutaneous leishmaniasis
• Old World:
– L. tropica,
– L. major
– L. aethiopica;
– May also produce L. infantum and L. donovani.
• New World:
– L. mexicana species complex
– L. [v.] braziliensis complex
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Cutaneous leishmaniasis
• 90% of the world's cases of cutaneous
leishmaniasis are in: Brazil, Peru & Middle east
countries 41
Cutaneous leishmaniasis
• 90% all cases of Cl occur in Afghanistan,
Brazil, Iran, Peru, Saudi Arabia and
Syria.
• 1-1.5 million new cases reported
annually worldwide.
• 90% of all cases of ML occur in Bolivia,
Brazil and Peru.
42
The clinical spectrum of Old World cutaneous
Leishmaniasis:
• Dry non ulcerative (Dry oriental sore):
– L. tropica.
• WET ulcerative (Wet oriental sore):
– L. major.
• Disseminated (diffuse) cutaneous
leishmaniasis:
– L. aethiopica.
• Chronic relapsing cutaneous leishmaniasis
(leishmaniasis recidivans)
– L. tropica.
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Cutaneous leishmaniasis life cycle
Inoculated promastigotes
engulfed by macrophage
cells
Promastigotes change into
amastigotes and multiply
within skin macrophages
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Cutaneous leishmaniasis life cycle cont.
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Cutaneous Leishmaniasis
Skin lesion appears as
Papules anodule
aulcer
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Single dry oriental sore
• Caused by L. tropica.
• Common in urban
areas
• Occur in exposed
body parts
• Single; Dry; non
exudative
• Pain less ulcers
• Self healing
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• Leave disfiguring
scars
• Patient become
immune to
reinfection
• Rarely develop
allergic state called
Leishmaniasis
recidivans (LR)
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Multiple wet oriental sore
• Rural type
• Cause by L. major
• Early papule inflamed
resemble boil
• Develop into large uneven
ulcer
• Healing occur 3-6 months
• Multiple lesions may occur
• Secondary bacterial infection
is common.
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Mutiple lesions by L.major
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Satellite papules
• Satellite papules of
cutaneous lesion
caused by L. major
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Disseminated (diffuse) cutaneous
leishmaniasis:
• L. aethiopica
• Lesion typical to
oriental sore
• Usually in face &
limb
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Diagnosis
• Clinical
• Laboratory
• Finding parasite from:
– Material obtained by
aspiration of fluid
around the edge of sore
– Biopsy
• Culture aspirate on
NNN
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Treatment
• pentavalent antimonials preparations:
– Local around the edge of the lesion
every 2-3 days for 3 doss
• Antibiotic for 2ry infections
• Cryosurgery
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Control
• Treatment of infected persons
• Destruction of reservoir hosts
• Sandfly control
• Preventive measures: screening, insect
repellent….
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