Trypanosoma cruzi is a species of parasitic euglenoid trypanosome

Trypanosoma

Trypanosoma is a genus of kinetoplastids , a monophyletic group of unicellular parasitic flagellate protozoa. The name is derived from the Greek trypano and soma because of their corkscrew-like motion. All trypanosomes are heteroxenous and are transmitted via a vector...

s. This species causes the trypanosomiasis

Trypanosomiasis

Trypanosomiasis or trypanosomosis is the name of several diseases in vertebrates caused by parasitic protozoan trypanosomes of the genus Trypanosoma. Approximately 500,000 men, women and children in 36 countries of sub-Saharan Africa suffer from human African trypanosomiasis which is caused by...

 diseases in humans and animals in America. Transmission occurs when the reduviid bug

Reduviidae

Reduviidae is a large, cosmopolitan family of predatory insects in the suborder Heteroptera...

 deposits feces on the skin surface and subsequently bites; the human host then scratches the bite area, which facilitates penetration of the infected feces.

Human American trypanosomiasis, or Chagas disease

Chagas disease

Chagas disease is a tropical parasitic disease caused by the flagellate protozoan Trypanosoma cruzi. T. cruzi is commonly transmitted to humans and other mammals by an insect vector, the blood-sucking insects of the subfamily Triatominae most commonly species belonging to the Triatoma, Rhodnius,...

, has two forms, a trypomastigote found in human blood and an amastigote

Amastigote

An amastigote is a cell that does not have a visible external flagella or cilia. The term is used mainly to describe a certain phase in the life-cycle of trypanosome protozoans. It is also called the leishmanial stage, since in Leishmania it is the form the parasite takes in the vertebrate host,...

 found in tissues.