LEISHMANIA HUMAN PATHOGENS Leishmania tropica Leishmania major Leishmania donovoni Leishmania mexicana Leishmania braziliensis

Classification Domain: Eukaryota Kingdom: Protista Phylum: Mastigophora Class: Kinetoplastida Order: Trypanosomatida Genus: Leishmania Species: donovani , tropica, major, maxima, braziliensis

Morphology i.e. Leishmania are heteroxenous Promastigiote in the gut of the fly Amastigote in the tissue of the vertebrate Leishman-Donovan body

Morphological terms Mastigote = flagella Check the position of the: Nucleus(Nu), Knetoplate(kt), undulating membrane(um) flagella(fg) & basal body(bb) Amastigote: Promastigote Epimastigote Trypomastigote

Examle: Amastigotes of Morphology Examle: Amastigotes of L donovani 10 mm K N H Indistinguishable from amastigotes of T cruzi Very small size, and absence of an emergent flagellum or undulating membrane Amastigotes of L. tropica or L. mexicana from skin lesions and L. braziliensis from mucocutaneous lesions would appear identical

Morphology…… Leishmania rosette In prepared slides you can see promastigotes aligning their nose in a circle, called a rosette.

Epidemiology Leishmania spp cause a major veterinary and public health disease in Latin America, Africa, Asia and the Mediterranean basin where 20-40% of dogs and 1-2% of children are infected They cause Leishmaniasis a disease affecting about 12 million people Mainly mammals – humans, dogs, several species of rodents Found in Africa through the Middle East and Asia Broadly overlaps the increasing HIV infection areas Evolving quickly to the population of hosts and vectors where it is found

Epidemiology…….. Dogs are main reservoir in the ‘old world’ In dogs Visceral leishmaniasis typically causes cutaneous lesions, with alopecia, depigmentation, hyperkeratosis, in addition to lymphadenopathy, deep visceral organ involvements.

Vector of Leishmania spp Life Cycle…….. Vector of Leishmania spp Lutzomyia spp. in the Central and South America (New World). L. mexicana Phlebotomus spp/ sand flies in Africa, Asia and Middle East. L. donovan

Genus Lutzomyia diabolica (sand fly) 1 mm Potential vector of Leishmania mexicana in the New World This is a non-biting male

Genus Phlebotomus (Sand Fly) Vector for leishmaniasis(old world)

Life Cycle Intermediate host and vectors are the sand flies - ~600 species Ingest the amastigote form, goes to mid- or hindgut to become promastigote, move to esophagus and pharynx, causes plugs in the digestive system, fly clears to the unsuscpecting host The vector bite the host or Can be crushed into skin or mucous membrane

Life Cycle…….. Mammals Reticuloendothelial system of spleen, liver, mesenteric LN, intestine and BM Dividing amastigotes in macrophage by binary fission  burst macrophage  free amastigotes  re-phagocytosed or ingested by fly  dividing promastigotes in fly gut  injected into bite wound, phagocytosed  dividing amastigotes in macrophage

Life Cycle Generally: It reproduces in the gut of a female sandfly, and migrates to her proboscis (mouth part). It is introduced into the human by her bite. It then enters a macrophage and becomes intracellular. Here, it loses its flagella and is now known as an amastigote.

Life cycle ……Leishmaniasis These amastigotes multiply in various organs including the spleen, liver, and lymph nodes. Symptoms include hepatosplenomegaly, lymph adenopathy, fever, weight loss, and a decrease in all blood cells: WBC, RBC, and platelets. The treatment is almost as bad as the disease because of the side effects. It is best to catch it early.

Leishmaniasis Life Cycle

Immunology and Treatment Problem is that the parasite lives in the macrophage where it lives in the phagolysome – degrades contents – evades the immune system Differ markedly in clinical manifestations Self-healing to fatal Treatment May alter clinical manifestastions Pentavalent antimonials – can be as severe as the disorder

L. tropica and L. major Cause cutaneous ulcer or oriental sore – cutaneous leishmaniasis also called Jericho, Aleppo or Dehli boil West Central, Middle East and Asia Minor into India

Pathogenesis of Lt and Lm Evidence takes a few days to several months Small red papule to a spreading ulcer May heal or become secondarily infected L tropica – found in more densely populated regions; many amastigotes; persists for months L major – found in sparsely inhabited areas; rapid ulceration; few amastigotes Diagnosis comes from finding amastigotes in scrapings from the outer edges of lesion

L. donovani Dum-Dum fever or Kala-Azar Asymptomatic or progressive – 2 to 4 months incubation Symptoms Low grade fever, malaise, protruding abdomen due to enlarged spleen/liver and eventual death Spleen is trying to make macrophages instead of RBC’s May also be acute – chills, fever to 104F, vomiting and death, also edema of the face, bleeding of mucous membranes, difficulty breathing and diarrhea

L. braziliensis Causes espundia, uta or mucotaneous leishmaniasis Found in Central Mexico and Northern Argentina Similar to other spesies Find LD bodies in tissues Once cured, lifelong immunity; if dormant – may re-occur

L. mexicana North Central America, Mexico, Texas and possibly the Dominican Republic and Trinidad Cutaneous form, increasing in numbers of infected 3 clinical manifestastions Cutaneous – Chiclero-ulcer Nasopharyngeal mucosal – rare manifestation Visceral – rare manifestation Sand flies is vector, disease is a zoonosis that has a main reservoir as rodents

Cutaneous Leishmaniasis Parasites form skin ulcers.

As many as 200 lesions may form causing disability and social stigma

Mucocutaneous Leishmaniasis Central & South America (new world) Destroys mucous membranes of nose & mouth

Visceral Leishmaniasis Kala Azar Primarily occurs in Africa and Asia. Characterized by irregular fever, weight loss, swelling of spleen & liver, & anemia. Fatality can be 90% if untreated.

Diagnosis and Treatment Males are more susceptible than females Probably due to the exposure to the sand fly Find Leishman-Donovan bodies in tissues or secretions Use monoclonal Ab in ELISA Dogs are main important reservior in most areas Oklahoma dog strain is endemic in the USA Chemotherapy is various antimony compounds

Visceral Leishmaniasis Liver section from a person with Visceral Leishmaniasis Higher magnification - showing infected host cells adjacent to uninfected hepatocytes Low magnification view - showing extensive infection of Kupffer cells by amastigotes

Vector - Gut sample -Promastigotes of L. donovani Stage found in the gut of the sand fly Undulating membrane is absence Anterior location of the kinetoplast (K) relative to the nucleus (N) K N

SUMMARY

TERMS Promastigote: has single flagella Amastigote: has no flagella Kinetoplast: round mass of circular DNA

Leishmania Life Cycle It starts out as a spindle-shaped, single flagellated cell called a promastigote (mastigote means flagella). You can also see the nucleus and a kinetoplast (mass of circular DNA). Kinetoplast

Leishmania rosette In prepared slides you can see promastigotes align their nose in a circle, called a rosette.

Leishmaniasis rosette

Leishmania donovani (Promastigote) Single flagellum found in sand flies

Leishmaniasis Macrophage rupturing Amastogotes Amastogotes with nucleus and kinetoplast

Leishmania Amastigotes

Sandfly This looks like a mosquito, except its body is hairy and the wings are feathery.

Leishmaniasis Cutaneous Mucocutaneus Visceral There are three forms of Leishmaniasis: Cutaneous Mucocutaneus Visceral

Cutaneous Leishmaniasis The disease is only at the site of the bite. This form is seen in Texas, Mexico, Asia, and the Middle East (our Iraq troops are coming down with this form). It manifests as a large, wet sore with raised edges. It looks like a volcano with weepy serum coming out of the center. The wound is not contagious, just the sandfly bite. Dogs can get this disease, too.

Leishmaniasis (cutaneous)

Leishmaniasis (cutaneous)

Leishmaniasis (cutaneous)

Leishmaniasis (mucocunateous) This is when the disease located in the mucous membranes of the nose and mouth. The most gruesome photos are of this form.

Leishmaniasis (mucocunateous)

Leishmaniasis (visceral) This is the most serious form. It occurs especially in immunocompromised people, especially HIV patients. The amastagotes reproduce inside macrophages. Only T-cells can kill infected macrophages, but HIV is a disease that infects T-cells. This form is known as Kala Azar.

Viscera Leishmaniasis Geographic Distribution: More than 90 percent of the world's cases of visceral leishmaniasis are in India, Bangladesh, Nepal, Sudan, and Brazil. Leishmaniasis is also found in Mexico, Central America, and South America, southern Europe, Asia, the Middle East, and Africa.

Kala Azar Hepatosplenomegaly

Kala Azar (duodenum)

African trypanasomiasis

Morphological terms/stages Mastigote = flagella Check the position of the: Nucleus(Nu), Knetoplate(kt), undulating membrane(um) flagella(fg) & basal body(bb) Amastigote: Promastigote Epimastigote Trypomastigote

Leishmania spp