African trypanosomiasis

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at September 5, 2016
StartDiseasesAfrican trypanosomiasis

According to the World Health Organization, African trypanosomiasis is present in 36 sub-Saharan Africa countries. The human African sleeping sickness or sleeping disease is transmitted through tsetse flies, so it is most commonly found in rural areas where animals are present. Infection rates are declining due to sustained efforts at disease control, but treatment nevertheless requires the work of skilled caregivers.

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Definition & Facts

This widespread tropical disease is spread by the bite of an infected tsetse fly. It is estimated that 60 million Africans are at risk for this potentially fatal disease. As the illness progresses, the treatment options become more complicated and risky.

It generally takes one to three weeks for the initial, nonspecific symptoms to appear, and this can lead to delays in the initial diagnosis and treatment. No vaccine is currently available, and prevention can be difficult due to the persistence of the tsetse flies. There are two types of African trypanosomiasis: East African trypanosomiasis and West African trypanosomiasis.

One of the challenges in treating African trypanosomiasis is that it essentially attacks the brain. In the late stage, the parasites, which are protozoans, are able to cross the blood-brain barrier and gain access to the central nervous system.

Symptoms & Complaints

The first warning sign of African trypanosomiasis is the presence of a tsetse bite. The flies are about the size of a honeybee, and their bites will generally leave a painful, red sore. These sores are typically firm. They will be tender, and fluid may collect just below the surface.

Research shows that the sore develops faster when more of the trypanosomes are present. One to three weeks later, nonspecific symptoms may develop, including:

In some cases, a skin rash may present. As the disease progresses, people may experience increased confusion, personality changes, and a range of neurological problems.

Patients may have problems with slurred speech, seizures, and difficulty walking as a result of the disease. Patients may sleep for long periods throughout the day only to suffer with insomnia at night. The infection can grow steadily worse and ultimately result in death within a few months.

West African trypanosomiasis has a longer incubation period than East African trypanosomiasis. This disease may not present for months or even several years.

Causes

The sleeping sickness is a vector-borne parasitic infection transmitted through flies. Specifically, it’s carried by the tsetse flies that are found in parts of Africa. It’s more commonly seen in rural areas where the people rely heavily on fishing, agriculture, animal husbandry, and hunting. These people are naturally more exposed to the flies, so infection rates are higher.

Direct exposure through a bite is not the only known cause. Mother-to-child infections can occur as the trypanosome is able to cross the placenta and infect an unborn child.

It is believed that other blood-sucking insects may contribute to the spread, but the tsetse fly is the primary culprit. There have also been documented cases of sleeping disease spreading through sex.

Diagnosis & Tests

Laboratory methods are used to diagnose sleeping sickness. The tests find the parasite in body fluids or tissues by viewing the samples under magnification. Some doctors will choose to take a biopsy of the sores to look for the parasites.

Once the parasites are detected, the cerebrospinal fluid through a lumbar puncture (spinal tap) will be examined to determine if the central nervous system has been compromised. Doctors will also try to determine the disease stage by looking at the white blood cell count and the presence of trypanosomes. This testing helps determine what level of treatment is required for the best prognosis.

Rapid diagnostic tests may be used but are generally less reliable than rapid diagnostic tests for malaria and HIV.

Treatment & Therapy

Treatments are adjusted based on the strain that is present and how advanced the disease is. Several of the drugs currently available have high toxicity levels, and the parasites may become more resistant to the treatment over time. Currently, there are four drugs that are commonly used for treating the sleeping sickness. These include:

People who are in the first stage of the disease will commonly be prescribed pentamidine or suramin. Once the disease progresses to the central nervous system, the treatment methods must change. One promising option for the advanced stage is the combination of eflornithine and nifurtimox. This method is generally considered safe, easy to administer, and reasonably effective. Skilled nursing professionals must administer this medication.

The medications are offered free of charge in a kit, and it comes with the necessary materials and equipment. World Health Organization nurses are highly trained and are generally available to manage the treatments and drugs. Only one drug, melarsoprol, is currently available to combat the disease in the very late stages.

Prevention & Prophylaxis

A vaccine for this disease is not currently available, and the preventive measures focus on limiting contact with tsetse flies. In general, local residents of an area know where the flies are most common and can advise visitors to avoid those spots.

People who are traveling in Africa are encouraged to wear long-sleeved shirts and pants to protect more of their skin and prevent bites. The flies are attracted to bright and dark colors, and they can bite through lightweight fabrics. Flies may enter moving vehicles, so people should check their automobiles before entering.

Insect repellent can also keep the tsetse flies away and reduce the risk of infection. Vector control is being used in some areas to effectively lower the number of tsetse flies through traps and screens.