Leishmaniasis

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2021年4月22日 (木) 17:24時点におけるVaccipedia.admin (トーク | 投稿記録)による版
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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
    • 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

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

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

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

emerging novel leishmaniasis

  • in Thailand
  • L. siamensis, L. martiniquensis