It's worth mentioning that disease vector carried by the tsetse fly is the vector for African sleeping sickness. The disease is caused by Trypanosoma rhodesiense or T. gambiense (no doubt named for the location on the continent of their first discoveries), which acts parasitically in the blood of humans as well as other vertebrates. The disease most commonly caused in other animals is called nagana.

It's also worth mentioning that the tsetse fly and the common housefly are in the same family.