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Sleeping sickness


Sleeping sickness is an infection caused by tiny parasites carried by certain flies. It results in swelling of the brain.

Alternative Names

Parasite infection - human African trypanosomiasis


Sleeping sickness is caused by two types of parasites Trypanosoma brucei rhodesiense and Trypanosomoa brucei gambiense. T b rhodesiense causes the more severe form of the illness.

Tsetse flies carry the infection. When an infected fly bites you, the infection spreads through your blood.

Risk factors include living in parts of Africa where the disease is found and being bitten by tsetse flies. The disease does not occur in the United States, but travelers who have visited or lived in Africa can be infected.


General symptoms include:

Exams and Tests

Diagnosis is often based on a physical examination and detailed information about the symptoms. If the health care provider suspects sleeping sickness, you'll be asked about recent travel. Blood tests will be ordered to confirm the diagnosis.

Tests include the following:


Medicines used to treat this disorder include:

  • Eflornithine (for T b gambiense only)
  • Melarsoprol
  • Pentamidine (for T b gambiense only)
  • Suramin (Antrypol)

Some people may receive a combination of these medicines.

Outlook (Prognosis)

Without treatment, death can occur within 6 months from cardiac failure or from T b rhodesiense infection itself.

T b gambiense infection causes sleeping sickness disease and gets worse quickly, often over a few weeks. The disease needs to be treated immediately.

Possible Complications

Complications include:

  • Injury related to falling asleep while driving or during other activities
  • Gradual damage to the nervous system
  • Uncontrollable sleep as the disease gets worse
  • Coma

When to Contact a Medical Professional

See your provider right away if you have symptoms, especially if you've traveled to places where the disease is common. It is important to begin treatment as soon as possible.


Pentamidine injections protect against T b gambiense, but not against T b rhodesiense. Because this medicine is toxic, using it for prevention is not recommended. T b rhodesiense is treated with suranim.

Insect control measures can help prevent the spread of sleeping sickness in high-risk areas.


Bogitsh BJ, Carter CE, Oeltmann TN. Blood and tissue protozoa I: hemoflagellates. In: Bogitsh BJ, Carter CE, Oeltmann TN, eds. Human Parasitology. 4th ed. Waltham, MA: Elsevier Academic Press; 2012:chap 6.

Kirchhoff LV. Agents of African trypanosomiasis (sleeping sickness). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, Updated Edition. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 279.

Review Date:11/14/2016
Reviewed By:Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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