Leishmaniasis

taxonomy

• phylum Sarcomastigophorea, class Zoomastigophorea, genus Leishmania
  • Plasmodium belongs to phylum Apicomplexa

morphology

• single flagellum
• kinetoplast - aggregation of DNA
• similar to Trypanosoma

epidemiology

• 700,000 - 1 mil. new cases per year

20,000-30,000 deaths per year

life cycle

• parasitize in human macrophage
• promastigote - 10-25 μm
  • with flagellum
  • transform from amastigote inside sandfly midgut
  • proliferate inside midgut
  • introduced into human skin directly from sandfly midgut during sandfly bite
  • phagocytized by macrophage
• amastigote - 2-4 μm
  • transform from promastigote and propagate inside macrophage
  • transform to promastigote inside sandfly midgut
• simpler than Trypanosoma
• vector: sandfly
• host: human, dog, rodent

sand flly

• Phlebotomus spp.
  • Eurasian
• Lutzomya spp.
  • Latin America
• Feed during night

clinical manifestation

visceral leishmania

• most serious
• same as Kala-azar
  • Latin "black fever"
• fever
• weight loss
• hepatosplenomegaly
• anemia
• 50,000-90,000 new cases per year
  • mainly children affected
  • India, Ethiopia, South Sudan, Brazil
• L. donovani
  • India, Africa
  • anthroponotic = maintained in human-to-human infection
• L. infantum (formerly L. chagasi was thought separated species)
  • Mediterranean, China, South America
  • dog is reservoir

diagnosis of visceral leishmania

• smear of bone marrow aspiration, lymph node or spleen aspiration
  • sensitivity 93-99% in spleen aspirate, 53-86% in bone marrow aspirate, 53-65% in lymph node aspirate
• culture in NNN media
• immunochromatographical detection of rk39 antigen
  • dip stick form

post kala-azar dermal leishmanisis (PKDL)

• skin manifestation after completion of Tx of visceral leishmaniasis
  • macular type, papular type, nodular type
• Leishmania may be detected from skin specimen in some cases
  • possible reservoir

cutaneous leishmania

• most common
• same as Oriental sore, Chiclero ulcer (in Latin America)
• papule, nodule → ulcer → scar
• basically self-limited
• rarely diffuce or disseminated
• 600,000-1 mil. new cases per year
• Afghanistan, Algeria, Brazil, Colombia, Iran, Syria
  • imported in Texas, US in 2015
• L. tropica, L. mexicana, L. amazonensis and other species >20
• Rhombomys opimus (great gerbil) is primary reservoir

• cutaneous leishmaniasis by L. donovani is reported in Sri Lanka

diagnosis of cutaneous leishmaniasis

• smear of fine needle aspirate or biopsy of skin lesion
• serological test is of no use; low sensitivity and variable specificity

mucocutaneous leishmania

• same as Espundia, white leprosy
• lyphatic or hematogenous dissemination to mucosa in mouth and/or upper respiratory tract, resulted in destruction and deformity of nose, palate, pharynx
• L. braziliensis, L. panamensis
• Bolivia, Brazil, Peru
• progressive ever without treatment
• secondary bacterial infection

diagnosis of mucocutaneous leishmaniasis

• leishmania is scarce in mucosal lesion
  • strong local immune response
• serology or molecular

emerging novel leishmaniasis

• in Thailand
• L. siamensis, L. martiniquensis