African Sleeping Sickness

Rhodesian Sleeping Sickness:

A more recent colonizer of people and therefore hasn’t developed a lot of the characteristics of an experienced parasite

African Trypanosomiasis

  • Mortality/Morbidity:

    • symptoms develop about 1 month after bite

    • there are four phases:

    • Phase 1: incubation period, trypomastigote in skin, red lesion and chancre at site of bite, painful., itching and inflammation of skin, lasts about 2 weeks

    • Phase 2: Trypomistagotes enter circulation, fever, headache, skin rash, duration is variable

    • Phase 3: Trypomistgotes collect in lymph nodes and channels, cells not invaded but there is proliferation of endothelial cells, infiltration of leukocytes, enlargements of lymph nodes in the cervical triangle

    • Phase 4: Invasion of the central nervous system - African Sleeping Sickness, headaches are severe, emaciation, mental dullness, Apathy, drowsiness, coma, death from asthenia, heart failure, meningitis, duration variable, often doesn’t occur in acute form because the person dies already

    • the parasites themselves are toxic, hyperstimulates the immune system, the surface of the parasite is constantly changing so it is harder to fight, compromises the immune system

  • Treatment is painful and toxic. Treatment once stage two begins is much harder to treat.

  • Diagnosis: Can find Trypanosomes in plasma,

  • the reported number of cases has been dropping steadily since the 1990s

  • recently has started flaring up again due to conflict

  • Treatments:

    • drug of choice used to be suramin (Bayer 205)

      • not effective against CNS forms

    • Melarsoprol (an arsenical; toxic) is used with Bayer 205 to treat CNS forms

      • vomiting, and kidney damage

      • 10% die from treatment

    • Ornidyl(DFMO) is the current drug of choice

      • tolerated well, effective against cns, 2 week treatment, $150

    • Experimental drug Fexinidazole is a 10-day course of one pill with a 97% cure rate

  • Other Negative Effects:

    • Depopulation:

      • Uganda 1901-1905': 100,000 → 30,000

    • Equality of life

    • lack of productivity in society

    • underweight cattle → overgrazing

    • presence of tsetse flies has led to the use of lots of pesticides which contaminate water with overuse