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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. |
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