Life-cycle stages of the
Trypanosomatidae
Trypanosomatidae exhibit a great number of different life-cycle
stages, which are shown in the figure below. The variety of stages
expressed depend on the species as well as on the host.
The life cycles of most African trypanosomes are similar. In the
vertebrate host (e.g., human) the parasite grows and reproduces as a
trypomastigote form in the blood of the infected host. When a vector
ingests trypomastigotes during a blood meal, the trypomastigotes
transform into epimastigotes and grow and reproduce in the vector's
gut or salivary glands. The epimastigotes transform into
trypomastigotes, and these infect a new host the next time a vector
takes a blood meal (view a diagram of the life-cycle).
The life-cycle of T. cruzi. comprises the epimastigote in the
insect gut and the intracellular amastigote in the macrophage.
The life-cycle of Leishmania spp. comprises the promastigote in
the insect gut and the intracellular amastigote and the
trypomastigote in the blood of the mammalian host.
Monoxenous (single host) trypanosomatids such as Crithidia,
Leptomonas and Herpetomonas live mainly in the insect gut as
promastigote, or choanomastigote stages.
|
|
The following stages are typical for each member of
theTrypanosomatid family:
- African trypanosome
- trypomastigote (mammal and insect)
- epimastigote (insect)
- American trypanosome
- trypomastigote (bloodstream of mammal)
- epimastigote (insect)
- amastigote (mammal, intracellular)
- Leishmania
- promastigote (insect)
- amastigote (mammal, intracellular)
- Crithidia
|
|
Life-cycle stages of trypanosomatidae. a,
promastigote; b, ophistomastigote; c,epimastigote; d,
trypomastigote; e, choanomastigote; f, amastigote; g,
paramastigote; h,....K, kinetoplast; N, nucleus; F,
flagellum.
|
|
Back to the table of contents
Continue
Last updated: 21 October 1997.
created by :Fred
Opperdoes