Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content ++ 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 T b gambiense causes West African trypanosomiasis and is transmitted in the moist sub-Saharan savannas and forests of west and central Africa Organisms are transmitted by bites of tsetse flies (Glossina species), which inhabit shaded areas along rivers Humans are the principal mammalian host, but domestic animals can be infected 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 ++ Demographics ++ The number of reported cases increased from the 1960s to1990s, and has since decreased greatly, 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 ++ Chancres at the site of the bite are uncommon Patient may be asymptomatic for months before hemolymphatic disease develops Hemolymphatic disease progresses to meningoencephalitic disease, which leads to coma and death ++ 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 ++ Somnolence, irritability, personality changes Severe headache Parkinsonian symptoms ++ Differential Diagnosis ++ T b rhodesiense infection Malaria Influenza and pneumonia Tuberculosis Infectious mononucleosis Leukemia or lymphoma HIV Arbovirus encephalitis Wilson disease Psychosis due to other causes, eg, neurosyphilis ++ Diagnosis ++ Laboratory Tests ++ During the hemolymphatic stage, detection of parasites in Giemsa-stained blood smears is difficult Serial specimens should be examined, since parasitemias vary greatly over time Meningoencephalitic (or second stage) disease is defined by the World Health Organization as CSF showing at least 5 mononuclear cells per mcL, elevated protein, or trypanosomes Concentration techniques can aid identification of parasites in blood or CSF Serologic tests are positive The simple card agglutination test for trypanosomes (CATT) Has excellent sensitivity and specificity Can be performed in the field However, the diagnosis should be confirmed by identification of the parasites Field-applicable immunochromatographic lateral ... GET ACCESS TO THIS RESOURCE Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth Get Free Access Through Your Institution Contact your institution's library to ask if they subscribe to McGraw-Hill Medical Products. Access My Subscription GET ACCESS TO THIS RESOURCE Subscription Options Pay Per View Timed Access to all of AccessMedicine 24 Hour $34.95 (USD) Buy Now 48 Hour $54.95 (USD) Buy Now Best Value AccessMedicine Full Site: One-Year Individual Subscription $995 USD Buy Now View All Subscription Options