Human african trypansomiasis (sleeping sickness)

Background

Caused by the protozoan parasite Trypanosoma brucei
- Two distinct sub-species exist T. brucei rhodesiense and T. brucei gambiense
  - rhodesiense - Eastern and Southeastern Africa
    - Transmitted by tsetse flies that live in woodlands on the savanah
  - gambiense - Central and Western Africa (More common of the two infections)
    - Transmitted by tsetse flies that live in denser vegetation and along rivers
  - Crude demarcation line runs through the Great Rift Valley
Endemic in 36 countries in Sub-Saharan Africa and about 30,000 are currently infected
Spread by the Tsetse fly
Data from 2009 and 2011 suggest that the prevalence is decreasing
The Democratic Republic of the Congo reported about 80% of new cases in 2012
Vertical Transmission (Mother to fetus) is also possible

Clinical syndromes produced by T. brucei gambiense and T. brucei rhodesiense are similar in nature, however the rhodesience strain is much more rapidly progressive and can present with fulminant disease over the course of a few months, not years like the gambiense strain
May present differently in travelers

Known as the hemolymphatic stage
Chancre
- May be earliest sign
- Painless, well circumscribed, rubbery lesion. (More common with rhodesiense sp.)
Winterbottom's sign
- Lymphadenopathy of posterior cervical lymph nodes-characteristic but not always present
Intermittent symptoms corresponding to waves of parasitemia
- Fever, headache, malaise, arthralgias, rash, pruritus

Direct visualization of the trypanosomes (Gold Standard)
- Blood smears with either Giemsa or Wright's stain
- Samples can include CSF, blood, lymph node aspirates, and chancre aspirates
  - Must examine CSF to staging and treatment purposes
- Low levels of parasitemia may require concentration of sample
Serologic testing
- Card agglutination test for trypanosomiasis (CATT)
  - Agglutination of freeze dried trypanosomes
- Useful for epidemiologic studies
CSF analysis
- Pleocytosis
- Elevated protein levels
- Mott cells
- Direct visualization of trypanosome
Imaging
- MRI - hyperintense signals in periventricular white matter
- EEG - Delta waves

Eflornithine (DMFO) for 14 days (T.b. gambiense only, no activity against T.b. rhodesience)
- Can combo with nifurtimox
  - More effective than Eflornithine alone
Melarsoprol for 12 days (T.b. rhodesience)
- Can combo with nifurtimox also
- Less effective than Eflornithine

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