What Is African Sleeping Sickness?

Infectious Disease May Lead to Fatal Sleep Condition

An African baby sleeps on his mother. Getty Images

There are a few infectious diseases that can severely alter sleep and may ultimately prove fatal. One of these is African sleeping sickness. What is African sleeping sickness? What are some of the clinical features? How is it diagnosed and how can it be treated? Read on to learn more about this condition.

What Is African Sleeping Sickness?

African sleeping sickness is a tropical infectious disease caused by a protozoan, Trypanosoma brucei, which is transmitted to humans through the bite of a tsetse fly.

There are two variants caused by distinctive trypanosomes, resulting in east and west African forms of the disease.

In total, African sleeping sickness occurs in 36 countries of sub-Saharan Africa. It is estimated that about 60 million people worldwide are at risk from developing the disease. Only a few hundred cases of east African sleeping sickness are reported each year. Approximately 10,000 cases of west African sleeping sickness occur annually, which represents good control compared to rates in the past.

Clinical Features and Symptoms of African Sleeping Sickness

African sleeping sickness has two clearly identifiable stages. If left untreated, the disease is fatal. Stage 1 is referred to as the hemolymphatic stage; stage 2 is the encephalitic stage.

After a minimum of five days from the infected tsetse fly’s bite, the first symptoms of African sleeping sickness develop. The skin reacts at the site of the bite and forms a trypanosomal chancre, a characteristic skin lesion.

The local lymph nodes, which function as sentry posts of the immune system, become infected, enlarged and painful (a condition called lymphadenopathy). Due to the blood and lymphatic system involvement, this first stage is referred to as the hemolymphatic stage.

As the disease progresses, fever develops.

The fever may vary over a period of weeks, which corresponds to the reproductive pattern of the parasites. In people infected with east African sleeping sickness, symptoms may be more severe and 10 percent will die without treatment. (This may occur when the heart muscle is affected.) Enlargement of the liver or spleen (hepatosplenomegaly) and a faint rash may also develop. Non-specific symptoms such as malaise, joint pain (arthralgia), generalized weakness and weight loss may also occur during this early stage.

In the second stage, referred to as the encephalitic stage, the brain becomes affected. This may occur within a few weeks in the east African type or months in the west African type. Affected people during this stage complain of headaches and difficulty thinking. They may be confused or have trouble concentrating. Psychiatric disturbance, such as irritability, personality changes, hallucinations, mania and suicidal tendencies, may develop. Uncontrolled movements, such as tremor or fasciculations (twitchy muscles), slurred speech (dysarthria) and painful sensations, may develop.

Sleep disturbances that are so characteristic of the disease also occur. There may be a spontaneous, uncontrolled desire to sleep. The circadian rhythm may become reversed, with daytime sleepiness and nighttime insomnia. Ultimately, these individuals enter a fatal somnolent (sleepy) state, which gives the condition its name. In addition, there may be seizures, incontinence, coma and, finally, death.

Diagnosis of African Sleeping Sickness

It can be difficult to diagnose African sleeping sickness. First, it is necessary to recognize that exposure is highly dependent on travel to, or life within, sub-Saharan Africa. People living in other areas of the world are not exposed to the disease.

Even in those who may be at risk of becoming infected, diagnosis can prove problematic. The parasite levels within the blood may fluctuate, requiring repeated microscopic examination or even lymph node biopsy. A specialized "card agglutination" test may be a useful complementary screening tool in west African trypanosomiasis. Further staging of the disease may be accomplished with a spinal tap (or lumbar puncture) to identify infection of the cerebrospinal fluid (CSF) that is typical of the encephalitic stage.

Treatment of African Sleeping Sickness

The number of drugs used to treat African sleeping sickness is limited and depends on the type and stage of disease. Stage 1 west African trypanosomiasis relies on pentamidine or, as a second-line therapy, either eflornithine or melarsoprol. When the disease progresses to involve the brain during the encephalitic stage, melarsoprol is the first choice and eflornithine is the second option.

In east African trypanosmiasis, stage 1 of the disease is treated first by suramin, with melarsoprol serving as a second-line option. If the disease progresses to stage 2, melarsoprol is used first and nifurtimox is added as a second-line therapy if needed.

These medications may have serious side effects. As an example, melarsoprol is a compound that contains arsenic and is associated with a 4 percent to 12 percent risk of death. Acute encephalopathy, which might be characterized by headaches or confusion, is a common adverse effect.

Moreover, availability of these medications has been problematic. Due to the limited application, these agents have not been profitable for the pharmaceutical industry. As a consequence, production has historically been interrupted at times. In addition, parasite resistance to the treatments has also occurred.

African sleeping sickness is one of the rare infectious diseases that can profoundly affect sleep. It is important to raise awareness about the condition, especially in order that medications may remain available to treat the afflicted.

If you return from Africa and believe you might be afflicted, you should contact your physician and the Centers for Disease Control and Prevention (CDC).

Sources:

Centers for Disease Control and Prevention. "Parasites - African Trypanosomiasis." Accessed May 2012.

Kennedy, P. "Human African trypanosomiasis of the CNS: current issues and challenges." The Journal of Clinical Investigation. 2004 Feb;113(4):496-504.

Stich, A. et al. "Human African trypanosomiasis." BMJ. 2002 Jul;325:203-206.

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