Sleeping Sickness

The first sign of sleeping sickness may be a sore appearing at the tsetse fly bite site about two to three days after having been bitten. Redness, pain, and swelling occur.

Two to three weeks later Stage I disease develops as a result of the protozoa being carried through the blood and lymphatic circulations. This systemic (meaning that symptoms affect the whole body) phase of the illness is characterized by a high fever that falls to normal then respikes. A rash with intense itching may be present, and headache and mental confusion may occur. The Gambian form includes extreme swelling of lymph tissue, enlargement of the spleen and liver, and greatly swollen lymph nodes. Winterbottom's sign is classic of Gambian sleeping sickness; it consists of a visibly swollen area of lymph nodes located behind the ear and just above the base of the neck. During this stage the heart may be affected by a severe inflammatory reaction particularly when the infection is caused by the Rhodesian form.

Many of the symptoms of sleeping sickness are actually the result of attempts by the patient's immune system to get rid of the invading organism. The overly exuberant cells of the immune system damage the patient's organs, anemia, and leaky blood vessels. These leaky blood vessels help to spread the protozoa throughout the patient's body.

One reason for the immune system's intense reaction to the Trypanosomes is also the reason why the Trypanosomes survive so effectively. The protozoa are able to change rapidly specific markers on their outer coats. These kinds of markers usually stimulate the host's immune system to produce immune cells specifically to target the markers and allow quick destruction of these invading cells. Trypanosomes are able to express new markers at such a high rate of change that the host's immune system cannot catch up.

Stage II sleeping sickness involves the nervous system. The Gambian strain has a clearly delineated phase in which the predominant symptomatology involves the brain. The patient's speech becomes slurred, mental processes slow, and he or she sits and stares or sleeps for long periods of time. Other symptoms resemble Parkinson's disease: imbalance when walking, slow and shuffling gait, trembling of the limbs, involuntary movement, muscle tightness, and increasing mental confusion. These symptoms culminate in coma, then death.