Overview

African trypanosomiasis, commonly called sleeping sickness, is an infectious disease caused by protozoan parasites of the species Trypanosoma, most often Trypanosoma brucei. The name "sleeping sickness" refers to the progressive disruption of sleep and wake cycles that can occur in late-stage disease. The term "sleeping sickness" is also sometimes used informally for other conditions such as narcolepsy, but those are unrelated disorders with very different causes.

Cause and transmission

The parasites are transmitted to humans through the bite of infected tsetse flies (Glossina species). These flies inhabit parts of rural Africa, particularly sub-Saharan regions where human and animal reservoirs overlap. Two subspecies of T. brucei cause human disease: one that typically causes a chronic form affecting mainly West and Central Africa, and another that produces a more acute illness in eastern and southern regions. Animal reservoirs—wildlife and livestock—can maintain transmission in some areas, increasing local risk (high-risk zones).

Symptoms and disease course

Infection usually begins with nonspecific symptoms and can progress in two main stages. Early (hemolymphatic) stage symptoms often include fever, headache, joint pains and swollen lymph nodes. If untreated, the parasite may invade the central nervous system and produce the late (meningoencephalitic) stage, characterized by behavioral changes, confusion, poor coordination and the hallmark disturbances of sleep, which give the illness its common name.

  • Early signs: fever, malaise, swollen lymph nodes, itching.
  • Late signs: sleep–wake cycle disruption, neurocognitive decline, motor abnormalities.
  • Two clinical forms differ in speed and severity; the chronic form may take months or years to progress, the acute form evolves more rapidly.

Diagnosis and treatment

Diagnosis is based on clinical suspicion in an endemic setting and confirmed by microscopic detection of the parasite in blood, lymph node aspirate or cerebrospinal fluid. Lumbar puncture is essential to determine whether the central nervous system is involved and to select appropriate therapy. Treatment regimens vary by stage and parasite type and have evolved over time. Early disease can be treated with less toxic agents, while late-stage disease has traditionally required drugs that cross the blood–brain barrier. Some older arsenic-derived medicines are effective against late-stage infection but carry substantial risks and require administration in a hospital. Modern combination therapies and newer drugs have improved safety profiles, though all treatments may produce significant side effects and must be managed carefully. For historical and pharmacologic context, one late-stage drug is known for being arsenic-based (arsenic) and thus associated with toxic effects (poison).

Epidemiology, impact and control

African trypanosomiasis has caused large outbreaks in the past and remains a public-health concern in parts of Africa. Sustained surveillance, vector control, screening of at-risk populations and prompt treatment have reduced case numbers from earlier peaks, but focal transmission persists. A large proportion of reported cases have occurred in the Democratic Republic of the Congo (DRC), and health agencies continue targeted efforts there and in other affected countries. Control strategies combine active case finding, insect control to reduce tsetse populations, and animal reservoir management where appropriate.

Prevention and notable facts

Prevention focuses on reducing exposure to tsetse flies and interrupting transmission chains. Practical measures include wearing neutral-colored clothing, avoiding known tsetse habitats, using insect repellents and window screens, and supporting community-based vector control programs. Because the disease can be fatal if untreated, early diagnosis and access to appropriate treatment remain critical. Distinguishing sleeping sickness from other causes of excessive sleepiness or neurologic symptoms is important for correct management; unlike narcolepsy, sleeping sickness is an infectious disease requiring antiparasitic therapy.

For further reading on parasite biology, vector ecology and clinical management consult specialized resources and public health guidance from organizations working in affected regions (treatment information, vector control, regional data).