African trypanosomiasis (sleeping sickness)
What is African trypanosomiasis (sleeping sickness)?
African trypanosomiasis, also known as sleeping sickness, is a disease spread by an infected tsetse fly, found in rural areas of sub-Saharan Africa. Sleeping sickness is caused by two different parasites, Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense. Most reported cases of sleeping sickness are caused by T. b. gambiense.
There is no vaccine or medication that protects against sleeping sickness.
What is my risk?
The risk for most travellers is low.
The risk is higher for travellers in sub-Saharan Africa who are:
- visiting or living in rural areas
- visiting game parks or other areas with thick vegetation
How is it transmitted?
Sleeping sickness is most commonly spread through the bite of an infected tsetse fly. Even in areas where the disease occurs, only a small percentage of flies are generally infected.
- Tsetse flies are the size of a honey bee and are grey-brown.
- They usually bite during the daytime and their bites are usually quite painful.
- A human becomes infected with Trypanosoma brucei parasites when an infected tsetse fly feeds on his or her blood.
The parasites that cause sleeping sickness, especially T. b. rhodesiense, can also infect cattle and wild animals.
In rare cases, sleeping sickness can also be spread:
- through a blood transfusion or organ transplant from an infected donor
- from an infected mother to her baby during pregnancy or delivery
What are the symptoms?
The symptoms of sleeping sickness differ if the infection is due to T. b. rhodesiense or T. b. gambiense.
Symptoms of T. b. rhodesiense infection:
Symptoms usually appear from three days to a few weeks after the bite from an infected tsetse fly and may include:
- painful chancre (small ulcer) at the site of the infected tsetse fly bite
- high fever
- severe headache and muscle aches
In rare cases, enlargement of the spleen, kidney problems, or heart problems can develop.
Neurological symptoms, like sleep disturbances, poor coordination, confusion and changes in behaviour, develop within a few weeks or months of initial infection.
If untreated, T. b. rhodesiense infection is usually fatal within weeks or months.
Symptoms of T. b. gambiense infection:
Symptoms usually appear months or even years after the bite from an infected tsetse fly.
Symptoms of T. b. gambiense infection are often non-specific, such as:
- headache and muscle aches
- swelling of the face
- swollen lymph nodes
- weight loss
Neurological symptoms, like sleep disturbances, poor coordination, and changes in behaviour, develop months to years after the initial infection.
If untreated, T. b. gambiense infection is usually fatal within several years.
The symptoms caused by T. b. rhodesiense become severe more quickly than the symptoms caused by T. b. gambiense.
Can African trypanosomiasis (sleeping sickness) be treated?
Treatment is available and depends on the stage of the disease.
Where is African trypanosomiasis (sleeping sickness) a concern?
Sleeping sickness is transmitted by tsetse flies in rural sub-Saharan Africa.
T. b. rhodesiense is found in eastern and southern Africa. Most cases of T. b. rhodesiense infection occur in Malawi, Tanzania, Uganda, and Zambia.
T. b. gambiense is found in central Africa and in some areas of western Africa. Most cases of T. b. gambiense infection occur in Angola, Central African Republic, Chad, the Democratic Republic of Congo, Republic of Congo, Sudan, and Uganda.
Consult a health care provider or visit a travel health clinic preferably six weeks before you travel.
- Protect yourself from tsetse fly bites
- Avoid areas with heavy infestations of tsetse flies.
- Remember to cover up:
- Wear long-sleeved, tucked-in shirts, long pants, shoes or boots (not sandals), and a hat.
- Tsetse flies can bite through lightweight fabric. Wear heavier fabrics.
- Tsetse flies are attracted by bright and dark colours. Wear light-coloured clothing or neutral colors that blend with the environment.
- Insect repellents may offer only limited protection against tsetse flies. However, this is still an option to consider, especially because the areas where sleeping sickness occurs overlap with areas where there are other insect-borne diseases, such as malaria and dengue.
- Inspect vehicles for tsetse flies before entering as they are attracted to the motion and dust from moving vehicles.
- In areas where sleeping sickness occurs, avoid blood transfusions and organ transplants unless it is an emergency.
- If you must receive a blood transfusion or organ transplant while travelling, try to confirm the donated blood or organ has been tested for sleeping sickness.
- If you cannot confirm the blood or organ has been screened, and you do not require emergency care, return home for treatment.
- Know the symptoms of sleeping sickness and see a health care provider if they develop.
- Symptoms of sleeping sickness may develop months after visiting a region where the disease occurs.
- Tell your healthcare provider where you have been travelling or living.
- Fact sheet: Human African trypanosomiasis (sleeping sickness), World Health Organization (WHO)