Sporadic cases are reported in Kenya. The risk is mainly restricted to Nyanza Province (with a recognized focus in the Lambwe Valley near Lake Victoria) and Western Province, extending along the border with Tanzania into the extreme southwestern part of Rift Valley Province.
Sleeping Sickness, also known as African Trypanosomiasis, is caused by the protozoa Trypanosoma brucei rhodesiense (also known as East African Trypanosomiasis) primarily found in woodland and savannah areas and can also infect cattle and wild animals. Trypanosoma brucei gambiense (also known as West African Trypanosomiasis) is mostly present in forests along rivers as well as water holes. The protozoa are transmitted by daytime biting infected tsetse flies belonging to the genus Glossina. African Trypanosomiasis is rarely acquired through blood transfusion.
>> Travel health advice on Chagas Disease.
Trypanosoma brucei rhodesiense is found in east and southern Africa and Trypanosoma brucei gambiense is found in west and central Africa. For reasons still unknown, the intensity of the illness can vary in different areas. Long term travellers going to rural areas, safari visitors, hunters, and game park wardens are at greater risk of being exposed to tsetse flies. Travellers visiting urban areas are not at risk.
Symptoms vary depending on the parasite, but they are much more acute with Trypanosoma brucei rhodesiense. If a person contracts T. b. rhodesiense, symptoms usually appear 1 to 2 weeks after the infection and include a red sore (chancre) at the site of the bite, severe headache, lack of appetite, insomnia, enlarged lymph nodes, muscle and joint pain, and sometimes a skin rash. The illness progresses after a few weeks to weight loss, as well as personality changes, slurred speech, seizures, difficulty balancing and walking resulting from central nervous system failure.
Trypanosoma brucei gambiense symptoms usually appear weeks or months after exposure to the protozoa although a chancre at the site of the bite develops 1 to 2 weeks after infection. The second phase of the illness usually becomes evident 1 to 2 years after infection and is characterized by fever, headache, muscle and joint pain, itchy skin, weakness, weight loss, insomnia, confusion, personality changes, slurred speech, seizures, difficulty balancing or walking, and hormonal imbalances.
Seek immediate medical attention if bitten by a tsetse fly (the bite is painful) and symptoms appear. If untreated, African Trypanosomiasis can lead to a coma and be fatal. Treatment includes taking antiparasitic drugs.
Travellers going on safari and rural areas should avoid getting bitten by tsetse flies. There is no preventive medication or vaccine against Sleeping Sickness.
Trypanosoma brucei protozoa images, life cycle, and distribution maps:
Information last updated: January 2020