Leishmaniasis is a parasitic disease with many clinical forms presented here.

1. PAR7O2: Etiology, Transmission, Life
Cycle And Pathology of Different
Clinical Forms of Leishmaniasis
Presented By
DINNYUY RENE KIVEN (SC20P279)
NGWENYI ANNIE-DORETTE (SC20P277)
Course Instructor:
Prof. Daniel Achukwi
June, 2021

2. OUTLINE
• Introduction
• Etiology
• Transmission
• Life Cycle
• Pathology
• References

3. INTRODUCTION
• Leishmaniasis is protozoal vector-borne diseases
• Affects both humans and animals
• Transmitted by the bite of a sand fly; Lutzomyia
(new world) and Phlebotomus (old world)
• Among the top ten neglected tropical diseases
with more than 12 million infected people
(PAHO/WHO, 2017 )

4. ETIOLOGY OF LEISHMANIASIS
• Can be caused by many species of Leishmania, a in the
family Trypanosomatidae (order Kinetoplastida)
• Approximately 30 species described in mammals
• Most are known to affect humans and/or domesticated
animals
• Few species have only been found in wild animals
• Additional species of Leishmania infect reptiles (lizards)
or have only been detected in insects so far

5. • Human visceral leishmaniasis is mainly caused by
Leishmania donovani and L. infantum
• L. chagasi is now considered to be a subspecies of L.
infantum
• Visceral leishmaniasis is occasionally caused by species,
normally associated with cutaneous leishmaniasis (e.g.,
L. tropica. L. braziliensis, L. amazonensis and L.
martiniquensis), as well as L. colombiensis and “L.
siamensis.”
ETIOLOGY cont

6. Western Hemisphere, Leishmania species that cause
human cutaneous leishmaniasis include members of the;
• L. braziliensis complex (L. braziliensis, L. panamensis, L.
guyanensis, L. shawi and L. peruviana,) and the
• L. mexicana complex (L. mexicana, L. amazonensis, L.
venezuelensis),
• As well as L. lainsoni, L. naiffi and L. lindenbergi
Species that cause cutaneous leishmaniasis in the Eastern
Hemisphere include
• L. tropica, L. major and L. aethiopica, which are all
members of the L. tropica complex.
ETIOLOGY cont

7. ETIOLOGY cont
Mucocutaneous leishmaniasis in the Western Hemisphere
is usually caused by
• L. braziliensis
• to a lesser extent, by L. panamensis, L. guyanensis, L.
amazonensis and L. peruviana. L. infantum, L. donovani,
L. tropica, L. major
• And L. aethiopica occasionally affect mucous
membranes in the Eastern Hemisphere

8. ETIOLOGY cont
In animals
• Two species, L. macropodum and L. enriettii, affect
animals but have not been found, to date in humans

9. The main species of Leishmania that cause human disease

10. Global distribution of 20 leishmania species pathogenic to
humans (Akhoundi et al., 2017)

11. TRANSMISSION
• Leishmania that infect mammals are
usually transmitted by phlebotomine
sandflies in the genera Phlebotomus and
Lutzomyia, which act as biological
vectors
• Each species of Leishmania is adapted to
development in specific species of
sandflies
• Members of the L. enriettii complex
might be an exception to sandfly-
mediated transmission: some evidence
suggests that biting midges might be the
most important vectors for these
organisms

12. • Sandfly activity occurs when it is humid and there is no wind
or rain
• Generally most active at dawn, dusk and during the night
(especially early in the night), but they will bite if they are
disturbed in their hiding places during the day
• Common hiding places include animal burrows, holes in trees,
caves, houses and other relatively cool, humid locations
• Sandflies are attracted to light and may enter buildings at
night
• Most species do not fly long distances, but there are a few
reports of sandflies traveling > 1 km
TRANSMISSION cont

13. • Other arthropods, including Culicoides sp. midges, ticks
and canine fleas have been suggested as possible
mechanical vectors for some Leishmania
• Unimportant in the epidemiology of leishmaniasis in
endemic area
• fleas and ticks might be involved in rare dog-to-dog
transmission of L. infantum where competent biological
vectors are absent
TRANSMISSION cont

14. • Reports of probable transmission via blood transfusions
in people and dogs
• via shared needles by intravenous drug users
• Transplacental transmission in dogs (L. infantum), mice
(L. mexicana) and humans (L. infantum)
• Human newborns can be infected whether or not the
mother was symptomatic
TRANSMISSION cont

15. • L. infantum has occasionally been transmitted between
dogs in the same household in the absence of sandflies
• Case histories suggest they might have been infected
during a fight, by licking a companion’s lesions, or by
ingesting blood during a hemorrhage
• Venereal transmission has been reported in dogs (L.
infantum) and experimentally infected mice
• Venereal transmission of L. infantum was also
documented in humans, but seems to be rare
TRANSMISSION cont

16. Sand flies transmitting most human
leishmaniasis

18. PATHOLOGY
Three forms of leishmaniasis
• Cutaneous
First described in the Old World (Lewis and Cunningham,
1876). Caused by Leishmania mexicana, Leishmania
amazonensis, Leishmania guyanensis, Leishmania panamensis
and Leishmania braziliensis
• Visceral
Caused by Leishmania donovani complex, which includes three
species: L. donovani, Leishmania infantum, and Leishmania
chagasi.
• Mucocutaneous
Caused by species belonging to the complex L. braziliensis,
which includes L. braziliensis, L. guyanensis, and L. panamensis

19. Cutaneous leishmaniasis
• Also called oriental sore, tropical
sore, Alepo boil etc
• involves only the skin, without
mucosal or visceral involvement
• Initially, one to multiple
erythematous papules, which may
sometimes be pruritic, appear on the
skin
• Papules can develop into ulcers,
which typically have raised, indurated
margins; nodules, which may be
smooth or covered in scales; flat
plaques; or hyperkeratotic wart-like
lesins

20. • Except in the ear, ulcers tend to remain
confined to the skin and do not affect the
subcutaneous tissues
• Skin lesions of leishmaniasis are usually
painless unless they become secondarily
infected or an ulcer lies over a joint
• L. major lesions tend to be exudative or
"wet," and prone to secondary bacterial
infections, while L. tropica infections tend to
be "dry," with a central crust
• Skin lesions may be accompanied by
regional lymphadenopathy, which
occasionally persists after the lesions have
healed.
Cutaneous leishmaniasis
L. Major lesion
L. tropica lesion

21. Cutaneous leishmaniasis
• Peripheral neuropathy has also been reported
• Many cases of cutaneous leishmaniasis remain localized;
however, secondary lesions sometimes appear on the
skin, or occasionally the mucosa, in other parts of the
body
• Most cases of cutaneous leishmaniasis heal
spontaneously, but this may take several months to a
year or more, depending on the species of Leishmania
• Some forms leave permanent scars

22. Diffuse cutaneous leishmaniasis (DCL)
• A rare form of skin disease, most commonly
caused by L. amazonensis and L. mexicana
• Patients with DCL, the skin lesions tend not to
ulcerate, but appear as nodules and papules
• Spread widely on the skin
• Lesions may cause damage to deep tissues
• Can persist indefinitely
• DCL can be incurable in some cases
Cutaneous leishmaniasis

23. Leishmaniasis recidivans
• often caused by L. tropica, L. braziliensis, L.
amazonensis, L. guyanensis and L panamensis
in Latin America
• Also been reported from other regions (e.g.,
Ethiopia) where these organisms are absent
• Leishmaniasis recidivans is an uncommon
condition
• Characterized by the development of new
lesions, typically plaques, in and around the
edges of a healed skin lesion
• The mucous membranes (e.g., nose and lips)
may sometimes be involved
Cutaneous leishmaniasis

24. Mucocutaneous Leishmaniasis
• usually occurs in Latin America
• Caused especially L. braziliensis
• Tends to occur 1-5 years aftercutaneous
leishmaniasis has healed
• Can also develop while skin lesions are still
present, or even in cases with no apparent
cutaneous involvement
• Initial signs are usually erythema and
ulcerations at the nares, followed by
destructive inflammation, with ulcers and
nodules that can spread to involve the nasal
septum, and in some cases, the oral cavity,
pharynx or larynx

25. • Frequent nosebleeds or itching in the
nose can be an early sign
• Lesions may eventually perforate the
nasal septum, cause severe
disfigurement of the face, or block the
pharynx or larynx
• The genitalia may also be involved
• Mucocutaneous leishmaniasis does not
heal spontaneously
Mucocutaneous Leishmaniasis

26. Visceral Leishmaniasis
• Also known as kala-azar, black fever, dumdum
fever
• most common symptoms are a prolonged
undulant fever, weight loss, decreased appetite,
signs of anemia, and abdominal distension with
splenomegaly and hepatomegaly
• In Africa, a primary granuloma sometimes
appears on the skin before systemic signs
become evident
• Thrombocytopenia may cause bleeding
tendencies, including hemorrhages on the
mucous membranes, and leukopenia can result
in increased susceptibility to other infections

27. • Some people who recover from visceral
leishmaniasis develop post-kala azar dermal
leishmaniasis (PKDL)
• PKLD tends to be caused mainly by L.
donovani
• characterized by a maculopapular, macular
or nodular rash that generally begins on the
face (especially around the mouth), but can
spread to the neck, torso and extremities
• In Africa, PKLD is common, usually occurs
within 6 months of visceral leishmaniasis (or
even concurrently), and often disappears
spontaneously within a year if the mucous
membranes are not involved
Visceral Leishmaniasis

28. Leishmaniasis in cameroon

29. References
• Issam Bennis, Vincent De Brouwere, Zakaria Belrhiti, Hamid Sahibi5 and Marleen
Boelaert. BMC Public Health (2018) 18:358 https://doi.org/10.1186/s12889-018-
5260-9
• MCGWIRE B.S. and SATOSKAR A.R. Leishmaniasis: clinical syndromes and treatment.
Q J Med 2014; 107:7–1.
• Hervé (1937). Note sur la leishmaniose cutanée au Cameroun. Ann. Méd. Pharm.
Colon. 35: 928-934.
• Djibrilla Kaou B, Ripert C, Ravisse P, Durand B, Carrie J (1979). Epidemiologic study of
the focus of cutaneous leishmaniasis in Mokolo (North Cameroon). Bull Soc Pathol
Exot Filiales.72(5-6):442-50.
• Centers for Disease Control and Prevention (CDC). Leishmaniasis
• Alemayehu B, Alemayehu M (2017) Leishmaniasis: A Review on Parasite, Vector and
Reservoir Host. Health Sci J. Vol. 11 No. 4: 519
• Henry J. C. de Vries , Sophia H. Reedijk ,Henk D. F. H. Schallig. Cutaneous
Leishmaniasis: Recent Developments in Diagnosis and Management. Am J Clin
Dermatol (2015) 16:99–109 DOI 10.1007/s40257-015-0114-z
• WHO, Current updates on Leishmaniasis, world Health Organization 2018.
• WHO, facts sheets-news/details/leishamnaiasis, world Health Organization 2020

30. Thank you