Trypanosoma Cruzi - Life Cycle

Life Cycle

Trypanosoma cruzi life cycle starts in an animal reservoir. These reservoirs are usually mammals, wild or domestic, and include humans. A triatomine bug serves as the vector. While taking a blood meal, it ingests T. cruzi. In the triatomine bug (Triatoma infestans), they go into the epimastigote stage. This makes it possible to reproduce. After reproducing through binary fission, the epimastigotes move onto the rectal cell wall. There, they become infectious. Infectious T. cruzi are called metacyclic trypomastigotes. Then, while the triatomine bug is taking a blood meal from a human, it defecates. The trypomastigotes are in the feces. Trypomastigotes are capable of swimming into the host's cells using flagella, a characteristic swimming tail dominant in the Euglenoid class of protists.

The trypomastigotes enter the human host through the bite wound or by crossing mucous membranes. The host cells contain macromolecules such as laminin, thrombospondin, heparin sulphate, and fibronectin that cover the surface of the host cells. These macromolecules are essential in the adhesion between parasite and host and the invasion process by the parasite of the host. The trypomastigotes must cross a network of proteins that line the exterior of the host cells in order to make contact and invade the host cells. The molecules and proteins on the cytoskeleton of the cell also bind to the surface of the parasite and initiate host invasion. When they enter a human cell, they become amastigotes. This is another reproductive stage. After reproducing through binary fission until a large amount of amastigotes are in a cell, pseudocysts are formed in infected cells. The amastigotes then turn back into trypomastigotes, and the cell bursts. The trypomastigotes swim along to either infect other cells or get sucked up by other reduviid bugs.