LEISHMANIASIS Dr. Ameer kadhim Hussein

M.B.Ch.B. FICMS (Community Medicine)

Leishmaniasis is one of the most important vector-borne diseases

of humans. This parasitic disease can be caused by many species of

Leishmania (over 20 Leishmania species), most of which are

zoonotic.

In humans, different species of the parasite are associated with

different forms of the disease.

Many Leishmania spp. cause skin ulcers and nodules. A few of

these organisms can also affect the mucous membranes, and may

cause disfiguring lesions of the nose.

Introduction

Other species damage the internal organs and cause human

visceral leishmaniasis which is a life-threatening condition.

Among domesticated animals dogs are the most important

species in the epidemiology of this disease.

Leishmania transmitted to humans by the bite of infected

female phlebotomine sandflies. Over 90 sandfly species are

known to transmit Leishmania parasites.

Types There are 3 main forms of the disease:

a. Cutaneous Leishmaniasis.

b. Mucocutaneous Leishmaniasis.

c. Visceral Leishmaniasis.

parasites leishmaniaMorphology of

in vertebrate hosts in sandfly vectors

Amastigote Promastigote

(Leishman body). (Leptomonad).

Sand fly

LeishmaniaLife cycle of species of

LeishmaniasisVisceral Identification: It is chronic systemic disease caused by intracellular protozoa of the

genus leishmania. The disease is characterized by fever, Hepato-

splenomegaly, lymphadenopathy, anemia, leukopenia,

thromboocytopenia and progrssive emaciation and weakness.

Untreated clinical disease is usually fatal.

Post kala-azar dermal leishmaniasis consist of macular, papular

and/or nodular skin lesions that occur weeks to years after

apparent cure of systemic disease. Post kala-azar dermal

leishmaniasis occur in about 50% of visceral L. in Sudan and in 10-

20% of cases in India.

Visceral Leishmaniasis

Girl suffering from visceral leishmaniasis – a potentially fatal condition, if

untreated - with markers showing signs of liver and spleen enlargement.

(Ethiopia).

Post kala-azar dermal leishmaniasis

Patient with post-kala-azar-dermal leishmaniasis. (Ethiopia)

Infectious agents: Typically Leishmania donovani , L. infantum and L.infantum/

chagasi.

Reservoir:

Humans , wild Canidae (foxes and jackals) and domestic dogs.

Incubation period: generally 2-6 months ranging from 10 days to years.

Period of communicability: Not usually transmitted from person to person but infectious

to sandflies as long as parasites persist in the blood or skin

of reservoir.

Infectivity for phlebotomines may persist after clinical

recovery of human patients.

Susceptibility:

Susceptibility is general. Kala-azar induce lasting

homologous immunity.

Mode of transmission:

1.Bite of infected female phlebotomine sandflies

(P. argentipes).

2.Personto person transmission has been reported in

leishmania –HIV co-infected IV drug abuser through

exchange of syringes.

Occurrence:

Visceral leishmaniasis is a rural disease occur in 62

countries. It is highly endemic in the Indian

subcontinent and in East Africa.

An estimated 200 000 to 400 000 new cases of VL

occur worldwide each year.

Over 90% of new cases occur in 6 countries:

Bangladesh, Brazil, Ethiopia, India, South Sudan and

Sudan.

Diagnosis based on: 1. Culture of the organism from a biopsy specimen or aspirated material.

2. Demonstration of intracellular amastigotes in stained smears from bone marrow, spleen, liver, lymph nodes or blood.

3. The PCR technique is the most sensitive, but remains expensive.

4. Serological diagnosis was traditionally based

on IFA and ELISA tests.

5. An antigen detection test in urine is also under

evaluation.

Methods of control A. Preventive measures :

No vaccine are currently available although candidate

vaccines are in development. Control measures are vary

according to the habits of mammalian hosts and habits of vectors

and include the following:

1. Case management : detect cases systematically and treat

rapidly this applied to all forms of leishmaniasis.

2. Vector control: apply residual insecticide periodically.

Phlebotomine are highly susceptible to control by systematic

spraying with residual insecticide. Spraying must include stone

walls, animal houses and rubbish heaps.

Insecticide –treated bed nets are also a good vector control

alternative which reduce the incidence of disease for example in

Syrian Arab Republic they reduce yearly incidence by 50-75% .

3. Eliminate rubbish heaps and other breeding places.

4. Destroy gerbils implicated as reservoirs in local areas by

deep plowing and removal the plants they feed on.

5. Avoid sandfly infested forest area especially when

sundown and use insect repellents and protective clothes if

exposure is un avoidable.

6. Apply environmental management and forest clearance.

7. Control dogs which regard as animal reservoir of parasites.

A young gerbil

Control patients, contacts and immediate

environment

1. Report to local health authority.

2. Isolation with blood and body fluid precautions.

3. Concurrent disinfection, quarantine, immunization of

contacts and investigation of contacts and source of infection: not

applicable.

4. Specific treatment: Pentavalent antimonials regard as first line

treatement in most countries. Sodium stibogluconate and

meglumine antimonate are most effective. Cases that do not

respond to antimony may be treated with amphotericin B or

pentamidine. Recently developed alternative drugs include (Miltefosine,

Aminosidine (paromomycin) and Sitamaquine).

Epidemic measures:

Effective control must include understanding of the local

ecology and transmission cycle and application of practical

measures to reduce mortality, stop transmission and avoid

geographical extension of the epidemic.

The measures used:

1. Case detection and effective treatment.

2. Vector control by indoor residual spray and using insecticide

treated bed nets.

3. Effective disease surveillance and program monitoring.

leishmaniasisCutaneous and mucosal Other names Baghdad boil , Delhi boil , oriental sore.

In Americas Espundia ,Uta and Chiclero ulcer.

It is polymorphic protozoan disease of skin and mucous membranes caused by

several species of the genus Leishmania. These protozoa exist as obligate

intracellular parasites in humans and other mammalian hosts. The disease

starts with a maculae, then a papule that enlarges and typically becomes an

indolent ulcer in the absence of bacterial infection.

Lesions may be single or multiple, occasionally non- ulcerative and diffuse.

Lesions may heal spontaneously within weeks to months, or last for a year or

more. In some individual certain strain (from Western Hemisphere) can

disseminate to cause mucosal lesions even years after healing of cutaneous

lesions.

Occurrence

Cutaneous leishmaniasis (CL) is the most common form of

leishmaniasis and causes skin lesions, mainly ulcers, on exposed

parts of the body, leaving life-long scars and serious disability.

About 95% of CL cases occur in the Americas, the Mediterranean

basin, the Middle East and Central Asia. Over two thirds of new

CL cases occur in 6 countries: Afghanistan, Algeria, Brazil,

Colombia, Iran and the Syrian Arab Republic. An estimated 0.7

million to 1.3 million new cases occur worldwide annually.

Mucocutaneous leishmaniasis leads to partial or total destruction

of mucous membranes of the nose, mouth and throat. Almost 90%

of mucocutaneous leishmaniasis cases occurs in the Bolivia,

Brazil and Peru.

Cutaneous leishmaniasis

Child with cutaneous leishmaniasis in Kabul, Afghanistan

Diagnosis is based on:

1. Microscope identification of the non-motile,

intracellular form (amastigote) in stained specimens

from lesions.

2. An intra-dermal (Montenegro) test with leishmanin,

an antigen derived from promastigotes, is usually

positive in established disease but it is not helpful

with very early lesions and immuno-suppressed

patients.

3. Serological (IFA or ELISA) testing.

Infectious agents:

Eastern hemisphere:

Leishmania tropica , Leishmania major , Leishmania

aethiopica.

Western hemisphere:

Leishmania braziliensis and Leishmania mexicana.

Reservoir:

locally variable including humans, wild rodents, and domestic

dogs.

Incubation period: At least a week up to many months.

Mode of transmission:

1.Bite of infective female phlebotomine sandfly. (P. papatasi and

P. sergenti).

2. Rarely through blood transfusion.

Period of communicability:

Not directly transmitted from person to person but the patient

infectious for sand fly as long as parasites remain in the lesions.

In untreated cases they can remain few months to 2 years.

Susceptibility: is general. Life long immunity may be present

after healing of lesions due to L.tropica and L.major but not

protect against other L. species.

Methods of control A . Preventive measures:

As mentioned in visceral leishmaniasis.

B. Control patients , contacts and immediate

environment:

1. Report to local health authorities.

2. Isolation, concurrent disinfection, Quarantine and

immunization of contacts: Not applicable.

3. Investigation of contacts and source of infection:

Interrupt the local transmission cycle in the most

practical fashion.

4. Specific treatment:

Medicines called antimony-containing compounds are the main drugs used to treatment.

These include:

Meglumine antimoniate.

Sodium stibogluconate.

Other drugs that may be used include:

Amphotericin B.

Ketoconazole.

Miltefosine.

Paromomycin.

Pentamidine.

Epidemic measures

Control the disease by:

1. Provision of adequate diagnostic and treatment

facilities.

2. Provision of adequate measures against

sandflies and mammalian reservoirs.

• There are 3 main forms of leishmaniases – visceral (often

known as kala-azar and the most serious form of the disease),

cutaneous (the most common), and mucocutaneous.

• Leishmaniasis is caused by the protozoan Leishmania parasites

which are transmitted by the bite of infected sandflies.

• The disease affects some of the poorest people on the planet,

and is associated with malnutrition, population displacement,

poor housing, a weak immune system and lack of resources.

• Leishmaniasis is linked to environmental changes such as

deforestation, building of dams, irrigation schemes and

urbanization.

Summary

• An estimated 1.3 million new cases and 20 000 to 30 000

deaths occur annually.

• Only a small fraction of those infected by Leishmania parasites

will eventually develop the disease.

Summary

Thank you