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Sleeping sickness   

Overview | Symptoms | Treatment | Prevention

Alternative names:

African trypanosomiasis

Definition:

Sleeping sickness is an infectious parasitic disease carried by tsetse flies from the Trypanosoma brucei family of parasites and characterized by inflammation of the brain and the covering of the brain (meninges).

Causes and Risks

Sleeping sickness is caused by two organisms, Trypanosoma bruceri rhodesiense and Trypanosoma bruceri gambiense. Rhodesiense produces the most severe form of the illness.

After a person is bitten by an infected fly, a red painful swelling develops at the site of the fly bite, similar to that seen in Chagas disease. From this site of inoculation, the parasite invades the blood stream causing episodes of fever, headache, sweating, and generalized enlargement of the lymph nodes. Parasites then invade the central nervous system (early with rhodesiense and later with gambiense) where they produce the symptoms typical of sleeping sickness.

Ultimately the parasites invade the brain, causing first behavioral changes such as fear and mood swings followed by headache, fever, and weakness. Simultaneously, the patient may develop myocarditis.

Death may occur within 6 months from cardiac failure or infection if the person is infected with rhodesiense. Gambiense infection may require up to 2 years before symptoms of infection in the central nervous system appear.

Gambiense-infected people develop drowsiness during the day, but insomnia at night. Sleep becomes uncontrollable as the disease progresses until the patient becomes comatose.

Risk factors include living in those parts of Africa where the disease is found and being bit by tsetse flies. The incidence is extremely low in the U.S., and is only found in travelers from those areas.

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