[Last Modified: ]
[Trypanosoma brucei gambiense] [T. b. rhodesiense]

During a blood meal on the mammalian host, an infected tsetse fly (genus Glossina) injects metacyclic trypomastigotes into skin tissue.  The parasites enter the lymphatic system and pass into the bloodstream .  Inside the host, they transform into bloodstream trypomastigotes , are carried to other sites throughout the body, reach other blood fluids (e.g., lymph, spinal fluid), and continue the replication by binary fission .  The entire life cycle of African Trypanosomes is represented by extracellular stages.  The tsetse fly becomes infected with bloodstream trypomastigotes when taking a blood meal on an infected mammalian host (, ).  In the fly’s midgut, the parasites transform into procyclic trypomastigotes, multiply by binary fission , leave the midgut, and transform into epimastigotes .  The epimastigotes reach the fly’s salivary glands and continue multiplication by binary fission .  The cycle in the fly takes approximately 3 weeks.  Humans are the main reservoir for Trypanosoma brucei gambiense, but this species can also be found in animals.  Wild game animals are the main reservoir of T. b. rhodesiense.