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Key Features

Essentials of Diagnosis

  • Exposure to tsetse flies

  • 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

General Considerations

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

  • The organisms are transmitted by bites of tsetse flies (genus Glossina), which inhabit shaded areas along streams and rivers

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

  • When the fly feeds again on a new mammalian host, the infective stage is injected

  • T b rhodesiense causes East African trypanosomiasis, and is transmitted in the savannas of east and southeast Africa

  • T b rhodesiense infection is primarily a zoonosis of game animals and cattle; humans are infected sporadically

Demographics

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

  • Infections are rare among travelers, including visitors to game parks

Clinical Findings

  • Chancres at the bite site; lesion is painful and measures 3–10 cm

  • Symptom onset usually occurs within a few days of the insect bite

  • The hemolymphatic stage includes intermittent fever and rash, but lymphadenopathy is less common than with West African disease

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

Diagnosis

  • Microscopic examination of fluid expressed from a chancre or lymph node may show motile trypanosomes or, in fixed specimens, parasites stained with Giemsa

  • During the hemolymphatic stage, detection of parasites in Giemsa-stained blood smears is common

  • Serial specimens should be examined, since parasitemias vary greatly over time

  • Meningoencephalitic (or second stage) disease is defined by the World Health Organization as cerebrospinal fluid (CSF) showing at least five mononuclear cells per microliter, elevated protein, or presence of trypanosomes

  • Concentration techniques can aid identification of parasites in blood or CSF

  • Serologic tests are also available

  • Field-applicable immunochromatographic lateral flow rapid diagnostic tests that cost less than CATT and are simpler to perform are available

  • Combining tests improves sensitivity and specificity

  • Molecular diagnostic tests, including PCR and field-friendly loop-mediated isothermal amplification (LAMP) are available, but these are not yet standardized or routinely available

Treatment

  • Pentamidine and eflornithine are not reliably effective

  • Suramin

    • Used to treat early disease

    • Dosing regimens vary: 100–200 mg test dose, then 20 mg/kg (maximum 1 g) intravenously on days 1, 3, 7, 14, and 21 or weekly for five doses

    • Toxicities include vomiting and, rarely, seizures and shock during infusions as well as subsequent fever, rash, headache, neuropathy, and kidney and bone marrow dysfunction

  • Melarsoprol

    • Used for CNS infection ...

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