At the advanced stage, the parasite invades the central nervous system. The patient suffers neurological disorders such as sleep disturbances, mental confusion and convulsions. Untreated, the patient falls into a permanent state of lethargy, followed by an irreversible coma and death. Sixty million people in 36 sub-Saharan countries live under daily threat of the disease, but only four million of them have access to diagnosis and treatment. Sleeping sickness strikes the poorest and most isolated communities in the poorest countries in the world.
Treatment relies on expensive drugs developed decades ago.
Melarsoprol, a key arsenic-derived drug for treating advanced stages of the disease, results in death in three to ten percent of patients. About five to ten percent of those infected will become sick or contagious at some point during their lives. TB occurs most frequently in the lungs, the principal site of infection. Symptoms include a prolonged cough, coughing up blood, chest pain, a change in overall health, and a moderate fever at night. Coughing, sneezing, talking or spitting pass the bacilli into the air, where they can remain for hours and be inhaled by others.