African Trypanosomiasis in Kenya
|Warning - Level 3, Avoid Nonessential Travel|
|Alert - Level 2, Practice Enhanced Precautions|
|Watch - Level 1, Practice Usual Precautions|
Released: March 12, 2012
What Is the Current Situation?
The form of trypanosomiasis seen in eastern and southeasthern Africa (rhodesiense) was recently reported in two European tourists who visited the Masai Mara National Reserve in Kenya. From 2000 to 2010, cases of human African trypoanosomiasis were reported in travelers who traveled to national parks, wildlife reserves, and game parks in Tanzania, Malawi, Zambia, and Zimbabwe.i Trypanosomiasis is a disease that has been historically found in this region of East Africa.
What Is African Trypanosomiasis (African sleeping sickness)?
African trypanosomiasis, also called African sleeping sickness, is caused by a parasite that is transmitted by an infected tsetse fly. The tsetse fly is found only in sub-Saharan Africa. Symptoms include fatigue, high fever, headaches, and muscle aches. If the disease is not treated, it is fatal. On average, the infection is reported in one US traveler per year; it is usually acquired in East African game parks.
How Can Travelers Protect Themselves?
No vaccine or drug can prevent African trypanosomiasis. You can prevent the disease by avoiding tsetse flies.
Tsetse flies are found in woodland and savannah areas, and they bite during daylight hours. If you are touring or hunting in a game park, you are most likely to be exposed to tsetse flies. Travelers to cities are not at risk. Take the following steps to avoid tsetse fly bites:
- Wear protective clothing, including long-sleeved shirts and pants. The tsetse fly can bite through thin fabrics, so clothing should be made of medium-weight material.
- Wear neutral-colored clothing. The tsetse fly is attracted to bright colors, very dark colors, metallic fabric, and the color blue.
- Inspect vehicles for tsetse flies before entering. The flies are attracted to moving vehicles.
- Avoid bushes. The tsetse fly is less active during the hottest period of the day. It rests in bushes but will bite if disturbed.
- Use insect repellent. Although insect repellents have not proven effective in preventing tsetse fly bites, they are effective in preventing other insects from biting and causing illness.
If you are bitten by a tsetse fly during your trip (the bite is often painful), watch for symptoms and see your doctor immediately if you get sick. Be sure to mention that you have been traveling in Africa and that you were bitten by a tsetse fly.
There are two types of African trypanosomiasis. East African trypanosomiasis is caused by the Trypanosoma b. rhodesiense parasite, which is spread by tsetse flies in eastern and southeastern Africa. West African trypanosomiasis caused by the T.b. gambiense parasite, which is spread by tsetse flies in in western Africa.
With East African trypanosomiasis, illness progresses more rapidly and symptoms generally appear within 1-3 weeks of the bite. Symptoms may include high fever, a sore at the site of the infective bite, skin rash, headache, muscle aches, and less commonly, enlargement of the spleen, kidney failure, or heart problems. Central nervous system involvement can occur within the first month of infection. If untreated it is fatal.
People infected with West African trypanosomiasis may remain without symptoms for many months after the bite. Symptoms and signs may include fever, headache, discomfort, muscle aches, facial swelling, itching, and weight loss. Central nervous system involvement occurs after months of infection and is characterized by drowsiness, severe headache, and a wide range of other symptoms, including mood disorders, behavior change, and endocrine disorders. If untreated, it is eventually fatal.
Diagnosis is made by microscopic identification of parasites in specimens of blood, chancre fluid or tissue, lymph node aspirate, or cerebrospinal fluid. Buffy-coat preparations concentrate the parasite. Parasitemias are higher in T. b. rhodesiense than in T. b. gambiense infection. Serologic tests are not helpful for diagnosis of T. b. rhodesiense. CDC can help arrange serologic testing for T. b. gambiense, which is not available in the United States. Diagnostic assistance is available through CDC’s Division of Parasitic Diseases and Malaria (www.dpd.cdc.gov/dpdx).
Medical treatment of East African trypanosomiasis should begin as soon as possible, based on the infected person’s laboratory results. Medication for the treatment of East African trypanosomiasis is available through CDC. Hospitalization for treatment is usually necessary. Periodic follow-up exams that include a spinal tap are required for 2 years.
- African Trypanosomiasis (from Yellow Book)
- African trypanosomiasis (from Division of Parasitic Diseases and Malaria)
- WHO Report on Global Surveillance of Epidemic-prone Infectious Diseases—African trypanosomiasis (Background of Surveillance with Map)
[i] Simarro PP, Franco JR, Cecchi G, Paone M, Diarra A, Ruiz Postigo JA, Jannin JG. Human African Trypanosomiasis in non-endemic countries (2000-2010). J Travel Med 2011; 19: 44-53.