Visceral leishmaniasis (VL), also known as kala-azar, is the most severe form of leishmaniasis caused by the protozoan parasite Leishmania donovani and transmitted by the infected sandflies. It characterized by irregular bouts of fever, substantial weight loss, swelling of the spleen and liver, and anaemia.

1. Visceral Leishmaniasis ( Kala azar)
Anup Muni Bajracharya

2. Key facts
• There are 3 main forms of leishmaniases – visceral (also known as kala-
azar, which is and the most serious formof the disease), cutaneous (the
most common), and mucocutaneous.
• Leishmaniasis is caused by the protozoanLeishmania parasites which are
transmitted by the bite of infectedfemale phlebotomine sandflies.
• The disease affects some of the poorestpeople on earth, and is
associatedwith malnutrition, population displacement, poor housing, a
weak immune systemand lack of financial resources.
• Leishmaniasis is linked to environmental changes such as deforestation,
building of dams, irrigationschemes, and urbanization.
• An estimated700 000 to 1 millionnew cases occur annually.
• Only a small fraction of those infectedby Leishmania parasites will
eventually developthe disease.
Source- https://www.who.int/news-room/fact-sheets/detail/leishmaniasis
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3. A.B

4. The cutaneous form presents with skin ulcers.
The mucocutaneous form presents with ulcers
of the skin, mouth, and nose.
The visceral form starts with skin ulcers and
then later presents with fever, low red blood
cells, and enlarged spleen and liver.
Visceral Leishmaniasis
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5. Causative agent-VL A.B

6. Habitat
• Promastigote forms of the
parasite are found in sand
fly.
• Intracellular Amastigote
forms are found in human
in reticuloendothelial cells
of the spleen, bone marrow,
liver, intestinal mucosa and
mesenteric lymph nodes.
A.B

7. Geographical distribution
• Visceral leishmaniasis (VL), also known as kala-azar is
fatal if left untreatedin over 95% of cases.
• It is characterized by irregular bouts of fever, weight
loss, enlargement of the spleen and liver, and anaemia.
• Most cases occur in Brazil, East Africa and in India. An
estimated 50 000 to 90 000 new cases of VL occur
worldwide annually, with only between 25 to 45%
reported to WHO.
• In 2018, more than 95% of new cases reported to WHO
occurred in 10 countries: Brazil, China, Ethiopia, India,
Iraq, Kenya, Nepal, Somalia, South Sudan and Sudan.
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8. Geographical distribution:- A.B

9. Morphology:
• The parasite exists in two forms:
• Amastigote and Promastigote.
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10. Amastigote
• Aflagellar stage of the parasite.
• found in man and other
mammalian hosts.
• found inside monocytes,
polymorphonuclear leucocytes
or endothelial cells.
• small, round to oval bodies
measuring 2-3 µm in length.
• known as LD (Leishman
Donovan) bodies.
• A rod –shaped kinetoplast lies
at the right angles to the
nucleus.
• It comprises of DNA containing
body and a mitochondrial
structure.
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11. Promastigote
• found in the digestive tract of
sand fly (vector) and in the
culture media.
• are long, slender and
splindle-shaped.
• measure 15 to 25 µm in
length and 1.5 to 3.5 µm in
breadth.
• A single nucleus is situated
centrally.
• The kinetoplast lies
transversely near the anterior
end.
• The flagellum is single,
delicate and projecting from
front.
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12. Life cycle of Leishmania donovani
• The parasite has two stages in its life cycle:
• Amastigote form: occurring in humans and mammals.
• Promastigote form: occurring in sandfly.
•
• Initiation - by the bite of infected female phlebotomine sand flies.
• Injection of infective stage (i.e., promastigotes) proboscis
during blood meals.
• Promastigotes phagocytized by macrophages and other
types of mononuclear phagocytic cells.
• Promastigotes transform into amastigotes in these cells.
• Amastigotes multiply in infected cells and affect different tissues,
depending in part on the Leishmania species
• Sandflies become infected during blood meals on an infected host
when they ingest macrophages infected with amastigotes
• In the sandfly's midgut, the parasites convert promastigotes ,
which multiply and migrate to the proboscis .
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13. Life Cycle
SOURCE
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14. Mode of transmission
• The infection is transmitted
to Human mainly by the bite
of vector
sandfly (Phlebotomus
argentipes).
• Less frequently the infection
is transmitted by:
• Blood transfusion, congenitial
infection, accidental
inoculation of cultured
promastigotes in the lab
workers.
• Males are affected more due
to increase exposure through
the occupation and leisure
activities.
A.B

15. Pathogenicity
• Visceral leishmaniasis, traditionally known as kala-azar ("black
fever", particularly in India), because of its characteristic symptoms.
• highly lethal if not treated properly.
• Incubation period - 3 to 6 months, and in some cases may be over a
year.
• In Indian leishmaniasis, incubation can be as short as 10 days.
• Target cells - mononuclear phagocyte system or reticuloendothelial
system
• The two main tissues of infection are spleen and liver.
• Clinical symptoms include
• pyrexia (recurring high fever which may be continuous or
remittent),
• enlargement of spleen and liver, and
• heavy skin pigmentation which darkens the physical appearance
(the reason for naming "black fever").
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16. Pathogenicity
• To a lesser extent - mucosa of the small
intestine and lymph nodes are also invaded by the
parasite.
• Morphological symptoms are noticeable particularly
on facial and abdominal regions.
• Skin becomes coarse and hard.
• In African infections, warty eruptions are common.
• In a fully developed stage, the patient
shows emaciation and anaemia.
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17. Picture Source:
https://www.who.int/leishmaniasis/visceral_leishmaniasis/en/

18. Laboratory diagnosis of leishmaniasis:
• Specimens:
• Splenic aspiration
• Bone marrow aspirations
• Lymph node aspiration
• Peripheral blood
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Source

19. Laboratory diagnosis of leishmaniasis:
• Microscopy: smear preparation
• The amastigotes of Leishmania
donovan is known as LD bodies
which can be demonstrated in
the smears of bone marrow, liver,
lymph node and peripheral blood
smear stained with leishman,
stains.
• LD bodies are seen within
macrophages.
• Some of LD bodies can also be
demonstrated free released from
the cells ruptures during making
of the smear.
A.B

20. Laboratory diagnosis of leishmaniasis:
• Culture
• About 1-2 ml of blood (also splenic and bone marrow
aspiration, other tissue and buffy coats of blood) is
taken aseptically and diluted with 10ml of citrated
saline solution.
• The cells are then either allowed to settle in a cool
incubator (22°C) overnight or centrifuged.
• At the end of each week, a drop of condensation fluid
is examined for promastigote forms.
• In a positive culture, motile promastigotes can be
demonstrated microscopically in a few days to 4 weeks.
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21. Laboratory diagnosis of leishmaniasis:
• Detection of antibodies
• Various serological test have been developed to
detect circulating specific antibodies for diagnosis
of VL.
• This include
• immunoenzymatic technique,
• immunoblot,
• IFA,
• ELISA,
• Westem blot.
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22. Direct Agglutination test (DAT)
• Widely used serological
test for diagnosis of
kala-azar
• Antigen used- trypsin
treated, stained and
formalin preserved
promastigotes.
• Positive reaction –
agglutination with
specific antibodies from
VL positive patient
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23. • The rk39 based
immunochromatgraphic test (ICT):
• Rapid dip stick test
• Antigen - recombinant k39
protien.
• K39 is an epitope apparently
conserved on amastigotes
of leishmenia spp
• Circulating anti-k39 IgG is
detectable in 95-100% patients
who have kala-azar, irrespective of
geographical region.
• Result can be obtained within 5
min.
• The test is found in dipstick format
that are more suitable for field
case.
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24. Treatment-Antileishmanial medicines
• Several medications are available.
• Commonly used medicines
include
• Pentavalent antimonials
(Meglumine antimoniate and
Sodium stibogluconate-also
known as Pentostam)
• Amphotericin B, paromomycin,
and miltefosine (Impavido).

25. Prevention & Control
• The best way for travelers to prevent infection is to
protect themselves from sand fly bites.
• To decrease the risk of being bitten, follow these
preventive measures:
• Avoid outdoor activities, especially from dusk to
dawn, when sand flies generally are the most
active.
• When outdoors (or in unprotectedquarters):
• Minimize the amount of exposed (uncovered) skin.
• Wear long-sleeved shirts, long pants, and socks
• Apply insect repellent to exposed skin and under
the ends of sleeves and pant legs.
• The most effective repellents generally are those
that contain the chemical DEET (N,N-
diethylmetatoluamide).

26. Prevention & Control
• When indoors:
• Stay in well-screened or air-conditioned areas.
• Sand flies are much smaller than mosquitoes and therefore can get
through smaller holes.
• Spray living/sleeping areas with an insecticide to kill insects.
• Use a bed net and tuck it under mattress. If possible, use a bed net
that has been soaked in or sprayed with a pyrethroid-containing
insecticide.
• The same treatment can be applied to screens, curtains, sheets, and
clothing (clothing should be retreated after five washings).