Leishmaniasis

taxonomy

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

morphology

• single flagellum
• kinetoplast
• 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
• papule, nodule → ulcer → scar
• 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

emerging novel leishmaniasis

• in Thailand
• L. siamensis, L. martiniquensis