1. Leishmaniasis
Fatima Al-Awadh

2. INTRODUCTION

3. Learning Objectives
1. Define and classify parasites.
2. Explain the pathogenesis of parasite.
3. Define leishmaniasis.
4. Mention the types & causes, risk
factors, signs & symptoms, diagnosis,
complications, treatment &
prevention.
5. Explain the life cycle of Leishmania.

4. What is a parasite ?
• A parasite is an organism that benefits
from a close prolonged relationship with
its host, which is harmed.
• The parasite grows, feeds, or uses
shelter of the host organism (including
the host itself) contributing negatively to
the relationship.
• May be ectoparasites or endoparasites
which can be intra- or extra- cellular

5. Classification
Medically Important Parasites
Metazoa Protozoa Chromista Fungi
• Multicellular. • Unicellular. • Unicellular. • Unicellular.
• Helminthes & • Fagellates, • Blastocystis • Microsporidia.
Arthropods. amoebozoa, hominis.
sporozoa &
ciliophora

6. Parasitic pathogenesis
• Given the wide diversity among human
parasites, the pathogenesis is highly
variable.
• Although the human parasites exhibit
direct pathogenic mechanisms, in most
instances the organisms themselves are
not highly virulent!

7. Parasitic pathogenesis
Exposure and Entry
Adherence and Replication
Disruption, Evasion, and
Inactivation of Host Defenses

8. 1. Exposure and Entering
Ingestion. Arthropod bite
Trans-placental
Direct penetration
penetration
Organism-directed
penetration

9. 2.a. Adherence
Mediated by
Physical Chemical
Mechanical or biting mouthparts. interaction between parasite surface
glycoproteins (adhesins) and
specific glycoprotein or glycolipid
receptors.

10. 2.b. Replication
• Parasites replicate intracellularly or
extracellularly in human
• Helminthes generally do not replicate.
• Temperature is important for the ability
to infect and cause disease.

11. Disruption, Evasion, and
Inactivation of Host Defenses
• Like other organisms, parasites elicit
humoral and cell-mediated immune
responses.
• parasites are particularly adept at
interfering with or avoiding these
defense mechanisms.
Antigenic variation,
Molecular mimicry & Intra-cellular location Immuno-suppression
Masking

12. What is leishmaniasis ?
• Leishmaniasis is an infectious disease
• caused by parasites belonging to genus
Leishmania
• generally transmitted by the bite of
infected female Phlebotomus sand fly.

13. Leishmaniasis types & causes
Cutaneous leishmaniasis (CL)
• Caused by L. major, L. tropica
& L. mexicana.
• The most common form.
• Days to few weeks.
• on the extremities and face.

14. Leishmaniasis types & causes
Mucocutaneous leishmaniasis
(ML)
• Caused by L. braziliensis.
• Not treated cutaneous lesion
on the face spreads to the
nose or mouth.
• Months to years.
• Lesions can be very
disfiguring

15. Leishmaniasis types & causes
Visceral leishmaniasis (VL)
• Caused by L. donovani, L.
infantum & L. chagasi.
• Most severe form of the
disease, fatal if untreated
• Visceral disease from the
Middle East is usually milder.

16. Leishmania forms

17. Life cycle of Leishmania

18. Types of leishmaniasis
“They have the same life cycle, but different
tropisms generating different symptoms”

19. Risk factors
• The major risk factor is being exposed
to infected sand flies.
• Infection is more common in adventure
travelers, Corps workers, soldiers.

20. Risk factors

21. SIGNS AND SYMPTOMS

22. Cutaneous Mucocutaneous Visceral
one lesion or initially a nodule at Sever weight loss
multiple lesions the bite of the sand
fly
large scaly, nodules inside the Pancytopenia
ulcerated plaques, nose, perforation of
or shallow ulcerated the nasal septum,
nodules and enlargement of
the nose or lips
expanding and Change in voice Hepatosplenomegaly
ulcerating over time
dry or weeping Intermittent fever
painful if secondarily Disfiguring scarring Hypergamma-
infected and tissue globulinemia
destruction
Swollen lymph nodes Dark skin
near the sores.

23. Diagnosis
• A physical exam may show an enlarged
spleen, liver, and lymph nodes. The patient
may have been bitten by sandflies, or was in
an area known for leishmaniasis.

24. Differential diagnosis
• Cutaneous leishmaniasis (CL) may look
like other skin diseases, especially
lepromatous leprosy, sarcoidosis, and
skin cancer.
• Visceral leishmaniasis (VL) may
resemble malaria or haematological
malignancies.
• Mucocutaneous leishmaniasis (ML) may
be similar to Tertiary syphilis.

25. Investigations
Cutaneous
Skin biopsy
CBC
Serologic testing

26. Visceral
Biopsy and culture of liver,
spleen, bone marrow, or lymph
nodes
Leishmania-specific PCR test
Indirect immuno-fluorescent
antibody test
Direct agglutination assay

27. Complication
• Fatal infections - due to immune system
damage
• Bleeding (hemorrhage) VL
• Facial disfigurement ML
• ruptured spleen VL

28. Treatment
Antimony-containing
Other drugs : Surgery
compounds :
• meglumine • Pentamidine: • Plastic surgery
antimonate. CL (ML).
• sodium • amphotericin • Splenectomy
stibogluconate. in drug-
resistant (VL).

29. Prognosis
Cutaneous Mucocutaneous Visceral
Localized cutaneous relatively resistant to Untreated visceral
leishmaniasis lesions treatment. leishmaniasis has a
usually heal 90% death rate, but
themselves completely. only a 10% death rate
Diffuse cutaneous with treatment.
leishmaniasis may
smolder on for years
without treatment

30. Prevention
Preventing sand fly bites is the most immediate
form of protection. You can prevent a bite by:
• Putting fine mesh netting around the bed
• Screening windows
• Wearing insect repellent
• Wearing protective clothing
• Public health measures to reduce the sandfly
population and animal reservoirs.
• There are no vaccines or drugs that prevent
leishmaniasis

31. Conclusion

32. References
• Merck manual, Pg 1379-1381
Medical microbiology, Pg 797-801
• http://www.youtube.com/watch?v=7poF
ARIxPoE
• http://www.medicinenet.com/leishmania
sis/page6.htm#what_is_the_prognosis_
of_leishmaniasis
• http://www.the-travel-
doctor.com/leishmaniasis.htm