Q: Your narcolepsy column did not mention African sleeping sickness. Can't that cause narcolepsy?


A: In 1902 Sir David Bruce discovered that sleeping sickness (also called African trypanosomiasis) is from an infection due to a parasite (trypanosome brucei) which is transmitted by the bite of a tsetse fly. Narcolepsy is a disease where sleep is not regulated properly due to deficiencies of certain brain chemicals.

There has been research done looking into the possibility that patients with sleeping sickness may have these same brain chemicals affected.

The tsetse fly is found in 36 countries in sub-Saharan Africa, usually in woodlands or areas of dense foliage, and is most active in the daytime. There are two types of trypanosome brucei, one more prevalent in Western and Central Africa, the other more prevalent in Eastern and Southern Africa. The parasites live and multiply in an infected mammal (including humans) and are then acquired by a tsetse fly that bites them. After about three weeks the parasite goes through another part of its life cycle and can be passed by a tsetse fly bite to another mammal. Even in high disease areas, only about one in 100 tsetse flies carry the parasite.

About 30 to 60 million people in Africa are at risk of getting the sleeping sickness. It is estimated that 300,000 to 500,000 people are infected, although only 30,000 to 50,000 cases of this under-diagnosed disease are identified yearly. This disease does not exist in the U.S., but it is rarely diagnosed (about one case per year) in people who have returned from Africa, most commonly having traveled to a game park in East Africa.

African sleeping sickness has two stages. Stage 1 is when the parasite is in the skin, lymph nodes and/or blood. Symptoms start about one to three weeks after the patient is bitten by a carrier tsetse fly. The patient may develop a red sore at the bite site (a chancre). They will then develop non-specific symptoms of fever, headache and/or joint pain. These symptoms are similar to other infections, including malaria, which is one reason the diagnosis may be missed. Patients may also develop a rash, swollen glands, body aches and an itch. This stage of the disease may last up to months or longer, and the symptoms may be mild and intermittent.

Stage 2, the neurological stage, is when the parasite crosses into the fluid around the brain (the cerebral spinal fluid or CSF). The symptoms include severe headaches, confusion, sense disturbances and poor coordination. As the disease progresses, the patient develops daytime fatigue and possible episodes where they cannot stop from falling asleep (hence the name sleeping sickness), as well as nighttime mania and insomnia.

If the infection is not treated it is always fatal.

The diagnosis of sleeping sickness is made by identifying the parasite in the patient's blood, lymph nodes, bone marrow, skin or CSF. Treatment for African sleeping sickness depends on the stage of the disease, so whether or not there is CSF involvement is key.

The medications used to treat stage 1 disease (for example, pentamidine) are usually better tolerated than those needed for stage 2 disease. One of the medications sometimes used to treat stage 2 disease is derived from arsenic and can cause encephalopathy (brain dysfunction) in up to 10 percent of patients.

Thankfully, recent research has shown that treatment with a combination of certain medications for stage 2 disease is efficacious and much better tolerated.

Patients treated for stage 1 disease usually have a complete recovery, and even those treated for early stage 2 disease do well, with over 90 percent having a full recovery. After successful treatment, the patient must be closely monitored for at least a couple of years for possible recurrence, including a spinal tap every six months to test the CSF.

There is no vaccine or medication to prevent sleeping sickness. Therefore, avoiding insect bites - a strategy used to prevent other diseases including malaria - is the best plan. Travelers are advised to wear neutral-colored medium-thick clothing (the tsetse fly can bite through thin material) from ankles to wrists, as well as a hat, insect repellent and covering for the neck and other places that might be bitten.

Returning travelers with any symptoms should have a high suspicion of having acquired an infection and should tell their health care provider about their travels.

However, with proper precautions, traveling can be safe, and the rewards of seeing other places and cultures can be huge.
