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Human African trypanosomiasis, sleeping sickness, is a parasitic disease of humans and other animals. Occuring only in 36 sub-Saharan Africa countries, it is caused by protozoa of the species Trypanosoma brucei and transmitted by the tsetse fly. There are two subspecies that infect humans, T.b. gambiense and T.b. rhodesiense, with the former accounting for over 98% of reported cases and the latter accounting for the remainder. Sustained control efforts have lowered the number of new cases reported to 6743 in 2011 and 7197 in 2012 respectively.

The disease progresses in two stages. In the first stage, trypanosomes multiply in subcutaneous tissues, blood and lymph, causing headaches, pain, and itching. In the second stage, the parasites cross the blood-brain barrier and infect the central nervous system. The more obvious symptoms of confusion, poor coordination, and sensory disturbances occur in stage two. Sleep-cycle disturbances are common and an impotant feature of this stage. Without treatment, sleeping sickness is fatal.

Diagnosis is made by screening for infection, determining is the parasite is present and finally assessing the state of disease progression. The long, benign first stage of the disease is why it is so important to do an exhaustive screening of populations at risk of infection.

Treatment depends on how far the disease has progressed. Drugs administered in the first stage are less toxic and more effective. Drugs adminstered to second-stage patients are complicated to administer and have high levels of toxicity. African Trpanosomiasis research at CERID is focused on drug discovery/development. 

Source: World Health Organization