Dealing with multiple environments: The challenges of the trypanosome lifecycle

African trypanosomes (Trypanosoma genus) are unicellular parasites responsible for infectious diseases that affect humans and animals. Human African trypanosomiasis is characterized by a markedly focal distribution that depends on complex interactions between parasite, vector, host and the environment, important aspects that are presented in this chapter. Trypanosoma brucei is a eukaryotic flagellated parasite that alternates extracellularly between two different hosts - the mammalian host and the arthropod vector - where it encounters very distinct microenvironments to which it must adapt in order to complete its complex developmental cycle and, eventually, be transmitted. An important and identifiable morphological feature of T. brucei is the presence of a single mitochondrion whose massive DNA, called the kinetoplast, is a diagnostic feature of the Kinetoplastida order. The authors speculated that it might reflect the need for active acquisition of glucose in a sugar-poor environment, providing a window for maturation of the mitochondrion.