Trypanosoma

Microbiology

• Flagellated vector-borne protozoan parasite of mammals in the genus Trypanosoma
• Generally have three morphological states: epimastigote, amastigote, and trypomastigote
  • T. cruzi has an intracellular amastigote while T. brucei do not, but rather multiply as trypomastigotes in the bloodstream
  • Amastigotes are commonly intracellular, and are small with a very short flagellum
  • Epimastigotes have a flagellum that runs along and connects as an undulating membrane, with the kinetoplast anterior to the nucleus
  • Trypomastigotes have a similar flagellum as epimastigotes, but with the kinetoplast posterior to the nucleus

Stages of trypanosomes

• Two major groups
  • Stercoraria, which multiply discontinuously in the mammal as amastigotes, and develop in the vector in the hindgut
    • Transferred via contaminated feces
    • e.g. T. cruzi
  • Salivaria, which multiply continuously in the mammal as trypomastigotes, and develop in the vector in the salivary glands
    • Transferred via saliva
    • e.g. T. brucei
• Three species infect humans
  • T. cruzi, which causes Chagas disease
  • T. brucei gambiense and T. brucei rhodesiense, which cause African sleeping sickness