Trypanosomes - life cycles

African Trypanosomes

1. Tsetse fly (DH) injects metacyclic trypomastigotes into human (IH)

2. Bloodstream trypomastigotes

3. Trypomastigotes binary fission

4. Tsetse feeds and ingests trypomastigotes from human

5. Bloodstream trypomastigotes in the midgut of fly replicate through binary fission

6. Trypomastigotes leave midgut and transform to epimastigotes

7. Epimastigotes replicated in salivary gland and then transform back to trypomastigotes.

Anterior station

Trypomastigotes

Kinetoplast near the posterior end.

Epimastigotes

Kinetoplast in the middle.

Amastigotes

Kinetoplast but no extending flagella.

Promastigote

Kinetoplast near the anterior end.

Anterior station

Transmission via bite (oral). Eg. African trypanosomes transmitted by tsetse proboscis.

Posterior station

Transmission via fecal route (poop). Eg. American trypanosomes where the bug poos out the trypomastigotes.

American trypanosomes - Trypanosoma cruzi: life cycle.

1. Bug injects trypomastigotes from bloodmeal.

2. Trypomastigotes transform into amastigotes in the cells

3. Amastigotes multiply by binary fission

4. Amastigote transform into trypomastigotes and burst out of the bloodstream

5. Bug takes blood meal and ingests trypomastigotes

6. Epimastigotes in midgut

7. Multiply in midgut

8. Metacyclic trypomastigotes in hindgut (posterior station)

Leishmania life cycle

1. Sandfly takes blood meal (injects promastigote into the skin)

2. Promastigotes in the macrophages or other mononuclear phagocytotic cells.

3. Promastigotes transform to amastigotes

4. Amastigotes multiply in cells and infect others

5. Sandfly takes blood meal (ingests macrophages with amastigotes)

6. Ingestion of parasitized cell

7. Amastigotes transform to promastigote stage in the gut

8. Divide and migrate to proboscis.

Anterior station.