Sleeping sickness is infection with organisms carried by certain flies. It results in swelling of the brain.

Sleeping sickness is caused by two organisms, Trypanosoma brucei rhodesiense and Trypanosomoa brucei gambiense. The more severe form of the illness is caused by rhodesiense.

Tsetse flies carry the infection. When an infected fly bites you, painful, red swelling occurs at the site of the bite. The infection then spreads through your blood, causing episodes of fever, headache, sweating, and swelling of the lymph nodes.

When the infection spreads to the central nervous system, it causes the symptoms typical of sleeping sickness (see below). When it reaches the brain, behavioral changes such as fear and mood swings occur, followed by headache, fever, and weakness. Inflammation of the heart ( myocarditis) may develop.

Risk factors include living in parts of Africa where the disease is found and being bitten by tsetse flies. The disease is extremely rare in the United States, and is only found in travelers who have visited or lived in those African areas.

Gambienseinfections lead to drowsiness during the day, but insomnia at night. Sleep becomes uncontrollable as the disease gets worse, and eventually leads to coma.

General symptoms include:

• Anxiety
• Drowsiness
• Fever
• Headache
• Increased sleepiness
• Insomnia at night
• Mood changes
• Sweating
• Swollen lymph nodes all over the body
• Swollen, red, painful nodule at site of fly bite
• Uncontrollable urge to sleep

A physical examination may show signs of meningoencephalitis (inflammation of the brain and its covering, the meninges).

Tests include the following:

• Albumin levels
• Blood smear
• Cerebrospinal fluid tests
• Complete blood count (CBC)
• Globulin levels
• Lymph node aspiration

Most antibody and antigen test are not very helpful because they can't distinguish between current and previous infection. Specific IgM levels in the cerebrospinal fluid may be helpful, however.

Medications used to treat this disorder include:

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

Without treatment, death may occur within 6 months from cardiac failure or from rhodesiense infection itself. Gambiense infection causes the classic "sleeping sickness" disease and gets worse more quickly, often over a few weeks. Both diseases should be treated immediately.

Complications include injury related to falling asleep while driving or performing other activities, and progressive damage to the nervous system.

Call your health care provider if you have symptoms of this disorder. It is important to begin treatment as soon as possible.

Pentamidine injections protect against gambiense, but not against rhodesiense. Insect control measures can help prevent the spread of sleeping sickness in high-risk areas.