What is African sleeping sickness?

Definition

African sleeping sickness, also known as African trypanosomiasis, is a parasitic
disease involving parasites belonging to the
Trypanosoma genus of protozoa. The disease is usually
transmitted by infected tsetse flies, which are found in sub-Saharan Africa. These flies live in
vegetation by rivers, lakes, and forests. There are two types of African sleeping
sickness, East African trypanosomiasis, which is caused by T. brucei
rhodesiense, and West African trypanosomiasis, caused by T.
brucei gambiense.

Causes

African sleeping sickness develops from an infection with protozoa. It
is not transmitted from person to person through direct contact. In very rare
cases, an infected pregnant woman can pass the disease to her fetus. An infected
person donating blood can also pass it into a blood bank, risking infection for
recipients in blood transfusions. When the protozoa reach the central nervous
system, they can cause behavioral and neurological changes leading to coma and
eventually death.

Risk Factors

A tsetse fly bite is the biggest risk for contracting African sleeping sickness. Therefore, for Westerners, travel to Africa, the natural habitat of these flies, creates the opportunity for transmission.

Symptoms

The initial symptom is a red swollen sore, called a chancre, at
the site of the tsetse fly bite. The disease then starts to spread into the
bloodstream, which causes fever, headache, lymphedema,
and sweating. As the parasitic infection reaches the nervous system, extreme
tiredness results. As African sleeping sickness progresses, irreversible
neurological damage occurs. Other symptoms that may occur include rash, tremors,
painful joints, swollen lymph glands, and muscle weakness. If the infection enters
the brain, seizures, irritability, and confusion are some of the symptoms that may
develop. Untreated, the disease may progress over months or years, finally leading
to coma and death.

Screening and Diagnosis

Diagnosis in the early stages of the disease can be made with a thick blood smear. The blood needs to be fresh to allow for good visualization of the protozoa. A number of sensitive techniques can be used to detect the parasite in the bloodstream; for example, the card agglutination trypanosomiasis test is used to screen for T. b. gambiense. Also, a spinal tap is performed and a sample of fluid taken from a swollen lymph gland.

Treatment and Therapy

The treatment of African sleeping sickness is dependent upon on the stage of the disease when first diagnosed. When the disease is recently acquired, less toxic drugs can be used to eradicate it. The earlier the disease is detected, the more probable the cure. When the disease is in the second stage of development, however, the medication must be able to cross the blood-brain barrier. Hospitalization is necessary, and periodical checkups are needed for two years. Late-stage disease may be untreatable.

Prevention and Outcomes

The only method of preventing African sleeping sickness is avoiding insect bites, which involves insect control programs and wearing protective clothing.

Some research shows that injections of the medication pentamidine show
favorable results in treating the early stages of T. b. gambiense
infection, while suramin is more effective against T. b.
rhodesiense. Eflornithine is used to treat
second-stage T. b. gambiense disease and resistant disease.

Bibliography

Bonomo, Robert A., and Robert A. Salata. “African Trypanosomiasis (Sleeping Sickness; Trypanosoma brucei Complex).” Nelson Textbook of Pediatrics. Ed. Richard E. Behrman, Robert M. Kliegman, and Hal B. Jenson. 20th ed. Philadelphia: Saunders, 2016. Print.

Braakman, H. M., et al. “Lethal African Trypanosomiasis in Travelers: MRI and Neuropathology.” Neurology 66 (2006): 1094-1096.

Centers for Disease Control and Prevention. “Parasites: African Trypanosomiasis.” Available at http://www.cdc.gov/parasites/sleepingsickness.

Maudlin, I., P. H. Holmes, and M. A. Miles, eds. The Trypanosomiases. Cambridge: CABI, 2004.