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Key Features

Essentials of Diagnosis

  • Exposure to tsetse flies; chancre at bite site uncommon

  • Hemolymphatic disease: Irregular fever, headache, joint pain, rash, edema, lymphadenopathy

  • Meningoencephalitic disease: somnolence, severe headache, progressing to coma

  • Trypanosomes in blood or lymph node aspirates; positive serologic tests

  • Trypanosomes and increased white cells and protein in cerebrospinal fluid (CSF)

General Considerations

  • African trypanosomiasis is caused by the hemoflagellates Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense

  • Organisms are transmitted by bites of tsetse flies (Glossina species), which inhabit shaded areas along rivers

  • Trypanosomes ingested in a blood meal undergo a developmental period of 18–35 days in the fly

  • T b gambiense

    • Causes West African trypanosomiasis

    • Transmitted in the moist sub-Saharan savannas and forests of west and central Africa

    • Humans are the principal mammalian host; domestic animals can be infected

  • T b rhodesiense

    • Causes East African trypanosomiasis

    • Transmitted in the savannas of east and southeast Africa

    • Infection is mainly of game animals and cattle; humans are infected sporadically


  • The number of reported cases has decreased greatly since the 1990s, although cases are reported from over 20 countries

  • Total incidence has been estimated at about < 5000 cases per year, the large majority due to T b gambiense, with the largest number in the Democratic Republic of the Congo

  • Infections are rare among travelers

Clinical Findings

Symptoms and Signs

West African trypanosomiasis

  • Chancres at the site of the bite are uncommon

  • Patient may be asymptomatic for months before hemolymphatic disease develops

  • Hemolymphatic disease

    • Fever, headache, myalgias, arthralgias, weight loss, and lymphadenopathy

    • Discrete, nontender, rubbery nodes, referred to as Winterbottom sign when in a posterior cervical distribution

    • Mild splenomegaly

    • Transient edema

    • Pruritic erythematous rash

    • Febrile episodes may be broken by afebrile periods of up to several weeks

  • Meningoencephalitic disease

    • Hemolymphatic disease progresses to meningoencephalitic disease, which leads to coma and death

    • Somnolence, irritability, personality changes

    • Severe headache

    • Parkinsonian symptoms

East African trypanosomiasis

  • Chancres at the bite site

    • More common than with West African trypanosomiasis

    • Lesion is painful and measures 3–10 cm

    • Regional lymphadenopathy appears about 48 hours after tsetse fly bite and lasts 2-4 weeks

  • More acute course than with West African trypanosomiasis

  • Hemolymphatic stage

    • Intermittent fever and rash

    • Lymphadenopathy is less common than with West African trypanosomiasis

    • Myocarditis can cause tachycardia and death due to arrhythmias or heart failure

  • Meningoencephalitic disease

    • Untreated hemolymphatic disease progresses over weeks to months to meningoencephalitic disease, somnolence, coma, and death

Differential Diagnosis

  • T b rhodesiense infection

  • Malaria

  • Influenza and pneumonia

  • Tuberculosis

  • Infectious mononucleosis

  • Leukemia or lymphoma

  • HIV

  • Arbovirus encephalitis

  • Wilson disease

  • Psychosis due to ...

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