Trypanosomiasis, African

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

Demographics

• 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 ...