Leishmaniasis Flashcards
What is leishmaniasis?
A vector-borne parasitic disease caused by protozoa of the genus Leishmania, transmitted by the bite of infected female phlebotomine sandflies.
What are the three main forms of leishmaniasis?
Cutaneous leishmaniasis (CL): Skin ulcers at the site of the sandfly bite.
Mucocutaneous leishmaniasis (MCL): Involves destruction of mucous membranes.
Visceral leishmaniasis (VL) (kala-azar): A systemic infection affecting internal organs.
Where is leishmaniasis most prevalent?
South Asia (India, Nepal).
East Africa (Sudan, Ethiopia).
Latin America (Brazil, Colombia).
Middle East.
What causes leishmaniasis?
Infection by Leishmania species
What is the vector for leishmaniasis?
Female sandflies of the Phlebotomus or Lutzomyia genera.
How does Leishmania infect the host?
Sandfly bite introduces promastigotes into the skin.
Promastigotes are phagocytosed by macrophages and transform into amastigotes.
Amastigotes multiply within macrophages, spreading to other tissues.
What factors influence the clinical form of leishmaniasis?
Host immune response: Strong Th1 response favors cutaneous disease; Th2 response predisposes to visceral disease.
Leishmania species.
What are the characteristic lesions of cutaneous leishmaniasis?
Painless, erythematous papules or nodules at the bite site.
Progress to ulcers with raised, indurated borders.
Often found on exposed areas (e.g., face, arms, legs).
How does mucocutaneous leishmaniasis present?
Nasal congestion, epistaxis.
Ulceration and destruction of nasal septum, palate, or pharynx.
Disfiguring lesions with risk of airway obstruction.
Which species commonly cause MCL?
L. braziliensis in Latin America.
What are the hallmark features of visceral leishmaniasis?
Fever, weight loss, and fatigue.
Hepatosplenomegaly.
Pancytopenia (anemia, leukopenia, thrombocytopenia).
Hyperpigmented skin (“kala-azar” or black fever).
What complications are associated with VL?
Secondary infections, bleeding disorders, and death if untreated.
How is leishmaniasis diagnosed?
Microscopy: Visualization of amastigotes in tissue smears or biopsies.
Culture: Promastigotes grown in NNN medium.
Molecular tests: PCR for species identification.
Serology: rK39 antigen test for VL.
What is the Montenegro skin test?
A delayed hypersensitivity test used in endemic areas to detect prior exposure to Leishmania (positive in CL and MCL).
What is the first-line treatment for cutaneous leishmaniasis?
Topical or intralesional antimonials for localized lesions.
Pentavalent antimonials (e.g., sodium stibogluconate) for widespread or severe cases.
