What Is The African Sleeping Sickness?

African sleeping sickness, also known as African trypanosomiasis, is a parasitic disease spread by the tsetse fly. It is found only in sub-Saharan Africa, in over 36 countries. If left untreated, the infection moves from the blood to the central nervous system, causing severe neurological symptoms and eventually death. The disease gets its name from the disruption of sleep cycles that happens in the late stage.

How Do You Get African Sleeping Sickness?

The only way to catch African sleeping sickness is through the bite of an infected tsetse fly. The fly carries a parasite called Trypanosoma brucei. There are two subspecies of this parasite, and they cause slightly different forms of the disease.

Trypanosoma brucei gambiense causes over 95% of all reported cases. It is found in West and Central Africa. This form is chronic, meaning symptoms can take months or even years to appear. Trypanosoma brucei rhodesiense is found in East and Southern Africa. It is much more acute, and symptoms can appear within weeks.

The tsetse fly lives in rural areas, particularly near rivers and forests. People who spend time outdoors in these regions — farmers, fishers, hunters, and travelers — are at the highest risk. The fly bites during the day. You cannot get the disease through casual contact with an infected person. No cases have ever been reported in the United States outside of travelers returning from Africa.

What Are the Symptoms of African Sleeping Sickness?

The disease has two stages. The first stage is when the parasite is in the blood and lymph system. The second stage is when it crosses into the brain and spinal cord. Symptoms are very different depending on the stage.

First stage symptoms typically appear 1 to 3 weeks after the bite. These include fever, severe headaches, joint pain, and itching. Many people also develop a red sore at the site of the bite called a chancre. Swollen lymph nodes are common, especially on the back of the neck. This stage is often misdiagnosed as malaria or the flu.

Second stage symptoms are neurological. The parasite invades the central nervous system, causing confusion, personality changes, poor coordination, and slurred speech. The most famous symptom is the disruption of the sleep-wake cycle. People experience uncontrollable daytime sleepiness and severe insomnia at night. Without treatment, the disease is fatal, usually within several months to a few years depending on the subspecies.

The CDC reports that the T. b. gambiense form can take months to years to reach the second stage. The T. b. rhodesiense form can reach the second stage in weeks. This difference is critical because it affects how quickly a person must be treated.

How Is African Sleeping Sickness Diagnosed?

Diagnosis requires a blood test. But it is not a simple one. The parasite must be seen under a microscope to confirm the infection. Doctors look for the parasite in blood smears, lymph node fluid, or bone marrow samples. Because the parasite can be hard to find, multiple tests are often needed.

If the first stage is confirmed, a lumbar puncture (spinal tap) is required to check if the parasite has reached the brain. This determines the stage of the disease and guides treatment. The World Health Organization (WHO) recommends specific diagnostic algorithms for different regions, depending on which subspecies is present.

Rapid diagnostic tests exist for the T. b. gambiense form. These are simple finger-prick tests that can be used in remote clinics. They are not perfect but have dramatically improved screening in rural areas. For T. b. rhodesiense, no rapid test is available, and diagnosis relies entirely on microscopy.

What Treatments Are Available for African Sleeping Sickness?

Treatment depends on the stage of the disease. The drugs for the first stage are different from those for the second stage. Treatment is complex and must be done under medical supervision. There are no home remedies or over-the-counter options.

Fexinidazole was a major breakthrough. It is the first all-oral treatment for the second stage of gambiense sleeping sickness. Before 2019, second-stage treatment required multiple intravenous infusions or a drug called melarsoprol, which killed about 5% of patients who took it due to severe brain inflammation. The WHO now recommends fexinidazole as the first-line treatment for most cases of gambiense sleeping sickness.

For rhodesiense, treatment options remain limited. Suramin is used for the first stage, and melarsoprol is still the only option for the second stage. Research published in The Lancet Infectious Diseases has called for more drug development for this form, which is rarer but more aggressive.

Is African Sleeping Sickness Preventable?

There is no vaccine for African sleeping sickness. Prevention relies entirely on avoiding tsetse fly bites. This is not easy for people who live or work in affected areas.

The CDC recommends several protective measures:

• Wear long-sleeved shirts and pants in neutral colors. Tsetse flies are attracted to bright and dark colors, especially blue and black.
• Use insect repellent that contains DEET on exposed skin.
• Avoid bushes and thick vegetation, where tsetse flies rest during the heat of the day.
• Sleep under insecticide-treated bed nets, even though tsetse flies bite during the day. Nets help protect against other biting insects as well.

Community-level prevention has been far more effective than individual measures. The WHO has run large-scale screening and treatment programs in affected countries. These programs test entire villages and treat everyone who is infected, even if they have no symptoms yet. This approach has dramatically reduced the number of cases. In 1998, there were nearly 40,000 reported cases. By 2020, that number dropped to fewer than 1,000. The WHO has set a target to eliminate gambiense sleeping sickness as a public health problem by 2030.

One non-obvious point: the tsetse fly is not the only way the parasite can spread. Very rarely, it can pass from a pregnant mother to her unborn child, or through blood transfusions and organ transplants. These cases are extremely uncommon but worth noting for healthcare workers in endemic regions.

What Is the Outlook for Someone with African Sleeping Sickness?

With early treatment, the prognosis is excellent. Almost all patients recover fully if treated during the first stage. Once the disease reaches the brain, treatment is still effective, but recovery is more complicated. Some neurological symptoms, like sleep disturbances or personality changes, may persist for months after treatment.

Without treatment, the disease is fatal. The rhodesiense form kills within weeks to months. The gambiense form can take years, but it is always fatal if left untreated. This is why surveillance and early diagnosis are so important in endemic regions.

Some people report that survivors of second-stage sleeping sickness experience ongoing fatigue and cognitive issues. Strong evidence on the long-term outcomes of survivors is limited. The WHO continues to monitor treated patients to understand these effects better.

For travelers who have been bitten by tsetse flies in an endemic area, the risk of infection is low. Most tsetse flies are not infected. But if you develop a fever, headache, or a chancre within a few weeks of returning, see a doctor and mention your travel history. The disease is treatable, but delay can be dangerous.