September 12th, 2010


Microbiology: African Sleeping Sickness

Sleeping sickness aka African trypanosomiasis
--parasitic disease in people and animals
--caused by protozoa of genus Trypanosoma
--transmitted by the tsetse fly
--endemic in certain regions of Sub-Saharan Africa (36 countries and 60 million people)
--estimated 50,000 to 70,000 current infx
--3 major epidemics: 1896–1906, 1920 and 1970.
--tse tse flies mainly found by rivers and lakes, in gallery-forests and in wooded savannah
--Sleeping sickness occurs only in sub-Saharan Africa in regions where there are tsetse flies that can transmit the disease.
--For reasons that are so far unexplained, there are many regions where tsetse flies are found, but sleeping sickness is not.
--Worldwide, 25,000 new cases of both East and West African trypanosomiasis are reported each year
--World Health Organization says it is vastly underreported.
--Human African trypanosomiasis (HAT)
--caused by flagellate protozoan, Trypanosoma brucei, which exists in 2 morphologically identical subspecies: Trypanosoma brucei rhodesiense (East African or Rhodesian African trypanosomiasis) and Trypanosoma brucei gambiense (West African or Gambian African trypanosomiasis)
--Both parasites transmitted to human hosts by bites of infected tsetse flies (Glossina species)
--tse tse flies are found only in Africa
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