Leishmania

Presented by:

Mahesh YadavM.Sc. II Yr.Central Department of Microbiology,T.U

INTRODUCTION

• Leishmania is a genus of trypanosomatid protozoa, which causes a fatal vector-borne parasitic disease called Leishmaniasis .

• It is spread by the bite of sandflies of the genus Phlebotomus in the Old World, and of the genus Lutzomyia in the New World.

• Leishmaniasis is the second-largest parasitic killer in the world (after malaria) and is endemic in many parts of Africa, Asia and South America.

HISTORY

• The parasite was named by Ronald Ross in 1903 after the Scottish pathologist William Boog Leishman.

• In 1901, Leishman identified the organism in smears taken from the spleen of a patient who had died from "dum-dum fever“.

CLASSIFICATION

• Kingdom• Subkingdom• Phylum• Subphylum• Class• Order• Genus• Species

ProtistaSarcomastigophoraProtozoaMastigophorazoomastigophoraKinetplastidaLeishmaniadonovani, tropica,

mexicana, braziliensis, etc.

IMPORTANT SPECIES

• L. donovani• L. tropica• L. mexicana• L. braziliensis

• L.major • L.guyanensis• L.lainsoni• L.naiffi• L.aethiopica, etc

HABITAT (L.donovani)

Are essentially the parasites of visceral organs. Promastigote forms found in sand fly and in culture. Amastigote forms found in man in reticuloendothelial cells of spleen, bone marrow, liver, intestinal mucosa, mesentric lymph node.

L.donovani L. tropica L.mexicana L. braziliensis

Parasites of Visceral organs

Skin Skin Skin and mucus membrane of nose and buccal cavity

Amastigote form found in

HumanReticuloendothelial cells of •spleen,• bone marrow ,• liver •intestinal mucosa

Human•Reticuloendothelial cells of skin

Human•Reticuloendothelial cells of skin

Human•Macrophage of skin•Mucous membrane of nose and buccal cavity

Promastigote form found in

Sand fly and culture

Sand fly and culture

Sand fly and culture

Sand fly and culture

HABITAT OF OTHER SPECIES

MORPHOLOGY(same in all species)

• The parasite exists in 2 forms;-

1. Amastigotes – aflagellar stage

2. Promastigotes- flagellar stage

Morphological Differences

Amastigotes

• Aflagellar stage

• Occurs in the vertebrate host

• divides by binary fission at 37oC.

• There are round or oval ;2-4µm along longitudinal axis.

• Nucleus relatively larger and situated centrally.

• Kinetoplast situated right angle to nucleus.

Promastigotes

• Flagellar stage

• Occurs in the sand fly

• divides by binary fission at 27oC.

• They are spindle shaped ;15-20 µm in length & 1-2µm in width.

• Nucleus smaller and situated in the middle of the cell or along the side of cell-wall.

• Kinetoplast lies transversely near the anterior end.

LIFE CYCLE (L.donovani)

Life cycle of other species of Leishmania are similar to L.donovani except that

In L.tropica•amastigotes reside in the large mononuclear cells of the skin

In L.mexicana•Amastigotes found in reticuloendothelial cells and lymphatic tissues of skin

In L.braziliensis •amastigotes are found in reticuloendothelial cells and lymphatic tissues of skin and mucus membrane

MODE OF TRAMSMISSION (L.donovani)

1. Mainly by the bite of sand fly (vector) Phlebotomus argentipus

2. Les frequently by • blood transfusion,• congenital infection, • accidental inoculation of cultured promastigotes in the lab.

workers, and• sexual intercourse.

Males are affected more (due to increased exposure to sand flies through the occupation and leisure activities).

RESERVOIR(L.donovani)

• Human:- in Indian subcontinent

• Rodents:- in Africa

• Foxes:- in Brazil and Central Asia

• Dogs :- In Mediterranean and China

L.donovani L.tropica L.mexicana L.braziliensis

Reservoir Man, rodents, foxes, dogs

Man,Dog

Sloth, ant eater, rat, dog

Sloth, ant eater, rat, dog

Vector Sand flyPhlebotomus argentipus

Sand fly Phlebotomus argentipus

Sand fly Lutzomyia spp.,

Sand fly Lutzomyia spp.,

Mode of transmission

•Bite of sand fly•blood transfusion•Congenital infection •sexual intercourse

Bite of sand fly •Bite of sand fly, •Bite of ticks ,•autoinfection

•Bite of sand fly, •Bite of ticks ,•autoinfection

Individual at risk

Males are affected more

Adolescents and young adults

Persons working at the edge of forest and in the people staying in rural areas.

Persons working at the edge of forest and in the people staying in rural areas.

Reservoir, vector and transmission of other species

VECTOR (Sand fly)

• Phlebotomas • Lutzomyia

CLINICAL MANIFESTATIONS

1. Pyrexia2. Spleen enlargement3. Lymphadenopathy 4. Darkening of the skin (KALA AZAR, MEANING “BLACK FEVER” IN HINDI, BECAUSE OF ITS

TENDENCY TO DISCOLOR ITS VICTIM’S COMPLEXION DURING ADVANCED STAGES)

5. Others:- kala-azar with HIV co-infection Post kala-azar dermal leishmaniasis(PKDL) Complications:- pneumonia, TB, dysentery, uncontrolled haemorrhage Prognosis:- With an early treatment, cure rate >90% If not treated, death occurs within 2 years.

CLINICAL MANIFESTATIONS OTHER SPECIES

L.tropica •Oriental sore•Acute necrotizing lesion•scar

L.mexicana •Chiclero ulcer•Indolent nodular lesionL.braziliensis •Espundia•Uta •Pian bois

TYPES OF LEISHMANIASIS

Leishmaniasis is divided into clinical syndromes according to what part of the body is affected most.

Visceral Leishmaniasis(VL)

Cutaneous Leishmaniasis(CL)

Mucocutaneous leishmaniasis(MCL)

Continued....

1. Visceral Leishmaniasis (VL) or Kala-azar

caused by L.donovani

part of the body affected most is internal organs

Spleenomegaly

Continued....2. Cutaneous

Leishmaniasis(CL) ( most common type)

a) Old world CL:- caused by L.tropica, L. aethiopica

b) New world CL:- caused by L.mexicana, L.braziliensis, L.guyanensis

c) Dermal leishmanoid or Post kala-azar dermal leishmaniasis(PKDL):- caused by L.donovani

Part of the body most affected is skin

....continued

3. Mucocutaneous leishmaniasis(MCL)

Caused by L. braziliensis and occasionally by L.panamensis

Part of the body affected most is skin and mucous membrane of nose and pharynx

SYNONYMS OF LEISHMANIASIS

Cutaneous leishmaniasis

Aleppo boil,

Baghdad boil,

Delhi boil,

Kandahar sore,

Lahore sore,

Oriental sore,

Visceral leishmaniasis

Kala-azar,

Black fever

Dum-Dum fever,

Sahib’s disease

Kala Dukh

White leprosy

Mucocutaneous Leishmaniasis

Breda's disease

bosch yaws, bush yaws

forest yaws

LABORATORY DIAGNOSIS

Peripheral blood by thick film method.(Amastigote

form)

Blood culture in N.N.N. Medium. (Promastigote

form) Biopsy material obtained by lymph node puncture,

sternal or iliac crest

puncture(marrow) and spleen

puncture(spleen pulp) only for

L. donovani

Indirect evidences

Blood count

Serum Tests

Other methods

Animal inoculation

Leishmanin or Montenegro Test

Adler’s test

Direct Evidences (contd......)

1. Peripheral blood by thick film method.(Amastigote form)

Amastigotes in a macrophage

Direct Evidences (contd......)

2. Blood culture in N.N.N. Medium. (Promastigote form)

Promastigote from culture in NNN medium

Direct Evidences (....contd)

3. Biopsy material obtained by

• lymph node puncture,• sternal or iliac crest

puncture(marrow) and• spleen puncture(spleen

pulp)

Amastigote form in a stained smear Promastigote in culture in NNN medium

Amastigotes of L. donovani. Splenic aspirate.

Indirect evidences

1. Blood count:- • Leucopenia (progressive)• Anaemia (raised ESR)

2. Serum Tests• Aldehyde test- positive after 3

months.• Antimony test- less reliable. Not

used now.• Complement fixation test with

W.K.K. antigen. Not used now.• Demonstration of antibodies

(ELISA, DAT, IHA, IFA with specific antigen etc.)

• Molecular diagnosis:- DNA Probes, PCR, etc.

Other methods

• Animal inoculation Wherever in vitro facilities are not there, the material from patients can be injected intraperitoneally in hamster or mice and the parasite is recovered from the animal. In positive cases, the amastigotes can be demonstrated in the stained impression smears of spleen from animals.

• Leishmanin or Montenegro Test It is a delayed hypersensitivity test. 0.2 ml of leishmania antigen

is injected intradermally. The test is read after 48-72 hrs. Positive result is indicated by an induration of 5mm or more. In kala-azar (visceral leishmaniasis), this test is negative

• Adler’s test:- It is a serological method. The development of promastigote forms of Leishmania in Locke’s serum agar can be inhibited by a immune serum specific to L.donovani, L.tropica and L.braziliensis.

EPIDEMIOLOGY

• Found in more than 88 countries.

• Found on every continent except Australia and Antarctica.

• For cutaneous leishmaniasis, number of cases range from 0.7 million to 1.2 million .

• For visceral leishmaniasis, number of cases range from 0.2 million to 0.4 million.

• Annual incidence of disease= 600,000 cases per year.

• People infected worldwide=12 million.

• People at risk=350 million.

GEOGRAPHICAL DISTRIBUTIONS

• Present worldwide.

• Most of the affected countries are in the tropics and subtropics.

• More than 90 percent of the world's cases of visceral leishmaniasis are in India, Bangladesh, Nepal, Sudan, and Brazil.

Leishmaniasis is found in • Asia (not Southeast Asia),• Central America, • South America (not in Uruguay, Chile, or Canada), • Southern Europe (not common in travelers to southern Europe), • The Middle East, and • Africa (particularly East and North Africa, )

Current Geographic Distribution of Leishmaniasis (....contd)

Leishmaniasis in Nepal

• Visceral leishmaniasis (kala azar) is common in the Terai region.

• The first confirmed case of VL was recorded in 1980.

• A total of 25890 cases with 599 deaths were reported during 1980-2006.

• During 2003, highest incidence (per 100,000) was in Mahottari district (184), followed by Sarlahi (100) and Sunsari (96).

• Highest case fatality rate (CFR) was in Dhanusha (2.9%) followed by Bara (2.4%) and Saptari (2.0%).

• Cutaneous leishmaniasis is rare in Nepal. • First case of cutaneous leishmaniasis was reported in the year 2006 in Nepal.

Leishmaniasis in Nepal (...contd.)

Reduction of reservoirby killing all the infected dogs in the cases of zoonotic kala-azar.

Education in the communityAbout the causes and modes of transmission of leishmaniasis.

Prevention of exposure to sand fly using insect repellent, bed nets and window mess as needed.

PREVENTION AND CONTROL

There are No Vaccines to prevent leishmaniasis.

PREVENTION AND CONTROL(.....contd.)

TREATMENTDrugs

Sodium stibogluconate solution Inhibits glycolytic enzymes and fatty acid

oxidation

Amphotericin B Binds with ergosterol leading to the altered permeability to cations, water, glucose and affect

membrane-bound enzymes.

PentamidineInhibits DHFR and interferes with aerobic glycolysis in

protozoa, also inhibits protein synthesis

MiltefosineEffects cell-signaling pathways and synthesis of the

cell-membrane

Interferonmacrophage activation

Specific therapy supplemented with

treatment of secondary microbial infections

high-calorie-high protein diet

Blood transfusion in severe anaemia

TREATMENT (....contd)

REFERENCES

• www.who.int• www.cdc.gov• www.Leishinfonet.com

• Chatterjee KD,(2009), Parasitology protozoology and helminthology, 13th edition, CBS publishers and distributers pvt. Ltd. New Delhi, India Page no.64-89

• Parija S.C., (2004), Textbook of Medical Parasitology, 2nd edition, All India publishers and Distributers. Page No.81-103

THANK YOU