Most Americans planning a summer safari in Zambia or Zimbabwe are thinking about malaria prophylaxis, yellow fever vaccination, and what camera lens to pack. Very few are thinking about tsetse flies — or the potentially fatal parasitic disease those flies can transmit in a single bite. The CDC maintains an active travel notice for East African Sleeping Sickness in Zambia and Zimbabwe, warning that several cases of East African human trypanosomiasis have occurred in travelers returning from safari areas in these countries — a resurging cluster that includes the first documented U.S. case from the Zambezi Valley since 2019.
East African Human African Trypanosomiasis (HAT), caused by the parasite Trypanosoma brucei rhodesiense and transmitted by infected tsetse flies, is classified as a neglected tropical disease and is invariably fatal without treatment. Unlike West African trypanosomiasis — which causes a slow, years-long progression toward neurological deterioration and the characteristic somnolence that gave sleeping sickness its name — the East African (Rhodesiense) form progresses in weeks to months. Left untreated, patients develop neurological involvement within days to weeks of the bloodstream stage and can die within weeks to months of the initial infection.
