African Trypanosomiasis

African Trypanosomiasis is an illness caused by the protozoa trypanosoma brucei gambiense and trypanosoma brucei rhodesiense and spread to humans through the bite of the tsetse fly.

Symptoms in humans can start with a large ulcer at the site of the bite of the tsetse fly, followed weeks or months later by fever, swollen lymph glands, enlarged liver and spleen. Later as the disease progresses one develops neurologic symptoms including daytime sleepiness; thus the description ‘sleeping sickness’.

Where does it occur?

 T.b. gambiense: Tropical rain forests of Central &West Africa(15N-20S latitudes)

 T.b. rhodesiense: Tropical rain forests of Central & East Africa(15N-20Slatitudes)

How is it transmitted?

 It is transmitted through the bite of the tsetse fly.

Is it contagious from person to person?

 It is not contagious from person to person.

What is the risk for travelers?

 Risk for travelers is usually low, long term visitors with prolonged exposure to forested areas with wild game and tsetse flies are at higher risk (game wardens/peace corps volunteers/missionaries etc.) Few cases among visitors to game parks have been reported.

How soon after exposure will one develop symptoms?

 Symptoms usually develop anywhere from weeks to months to possibly years after exposure with T.b. gambiense. Symptoms usually develop within days to few weeks after exposure with T.b. rhodesiense

What are the signs and symptoms?

 Symptoms usually start 1-2 weeks after the tsetse fly bite with a swollen, painful ulcer at the site of the bite that can be an inch in diameter, associated with fever and swollen lymph glands and heals over a few weeks.

Weeks to months later there is the onset of high fever alternating with days of normal temperature. This is associated with swollen, painless lymph nodes of the neck, especially the back of the neck (winterbottom sign). Frequently there is also swelling of the face, hands or feet that comes and goes, with a red circular rash that is itchy.

As the protozoa enters the central nervous system, symptoms develop over a period of weeks to months later with changes in personality, difficulty concentrating, irritability, progressive sleepiness during the day and restlessness at night. As symptoms progress one sees tremors, unsteady gait, slurred speech, coma and death.

West African trypanosomiasis is characterized by a prolonged course of illness, while East African trypanosomiasis tends to have a more rapid onset of symptoms and progression occurring over days to weeks, rather than months to years.

Is there any treatment?

 Medication called Benznidazole is effective in treatment.

Are there any lab tests to diagnose illness?

 The parasite can be seen in blood and spinal fluid using the microscope after concentration methods are used to process the specimen. The parasite can be cultured from blood and spinal fluid. Antibody tests are available to be performed on blood and spinal fluid but are of limited value currently.

What preventive measures can be taken?

 Take insect safety precautions.

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