Sleeping Sickness- African trypanosomiasis
This was one of the most frightening of all tropical diseases - smoldering and slowly killing the victim by inflicting a fatal indifference. It is caused by infestation with the trypanosome parasite spread by the bite of the tsetse fly. Perhaps the most eloquent description of sleeping sickness was penned by Dr. Albert Schweitzer in the early part of this century, then working in Gabon. Here from On the edge of the primeval forest:
Whenever it gets into a new district it is terribly
destructive, and may carry off a third of the population. In
Uganda, it reduced the number of inhabitants in six years from
300,000 to 100,000. An officer told me that he once visited a
village on the upper Ogowe which had two thousand inhabitants.
On passing it again two years later he could only count 500; the
rest had died meanwhile of sleeping sickness.
The first symptom consists of irregular attacks of fever,
sometimes light, sometimes severe, and these may come and go for
months without the sufferer feeling himself really ill. There
are victims who enter the sleep stage straight from this
condition of apparent health, but usually severe headaches come
during the fever stage. Many a patient have I had come to me
crying out: "Oh doctor! My head! My head! I can't stand it any
longer; Let me die!" Again, the sleep stage is sometimes
preceded by torturing sleeplessness, and there are patient who
at this stage get mentally deranged; some become melancholy,
One of my first patients was a young man who was brought because
he wanted to commit suicide. Sooner or later, however, though it
be two or three years since the first attacks of fever, the
sleep sets in. At first it is only an urgent need of sleep; the
sufferer falls asleep whenever he sits down and is quiet, or
just after meals.... Towards the finish the sleep becomes
sounder and the sick man lies without feeling or perception.
African trypanosomiasis is caused by one of two parasites (Trypanosoma brucei gambiense and T. b. rhodesiense) which enters the bloodstream with the bite of an infective tsetse fly. The organism then invades other tissues, having a predilection for the central nervous system. This large brown fly bites in the daytime, and although humans are not its preferred host, it will settle - those at risk are frequently out for prolonged periods during the day time in areas of game activity - honey-gatherers in Malawi, for example, are at high risk. If caught in time, this disease can be treated.
About 20-50,000 new cases are found each year, limited to a band of sub-Saharan Africa from the West coast to Kenya. The above number may be under-reported due to fragmentation of health systems in these socially and politically volatile countries. Treatment is available if the disease is recognized before brain damage develops.
Note that American trypanosomiasis, caused by the similar T. cruzi, generally does not involve the central nervous system. The organisms have slightly differing appearances under the microscope, involving the location of a darkly-staining chromatin body (terminally located in T. cruzi, located centrally in African strains).