Magnified 1000X, this Giemsa-stained light photomicrograph revealed the presence of Trypanosoma brucei parasites, which were found in a thin film blood smear. 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.
T. b. gambiense is found in foci in large areas of West and Central Africa. The distribution of T. b. rhodesiense is much more limited, with the species found in East and Southeast Africa.