Why does t. brucei infection cause the symptoms that led to the term "African sleeping sickness"?
The African Sleeping Sickness is a prevalent disease in sub-Saharan Africa. It is caused by the Trypanosoma brucei, a parasitic protozoan carried by the tsetse fly. There are two strains of the African Sleeping Sickness. the first type is caused by the t. brucei gambiense. More than 98% of the accounted cases are caused by this strain.
The other strain is the Trypanosoma brucei rhodesiense. The symptoms of this disease are as follows: extreme fatigue, fever, irritability, severe headache, muscle and joint aches, swollen lymph nodes and skin rash. The parasite invades the central nervous system once it crosses the brain barrier.
For patients infected with the t.b. rhodesiense, the progression of the symptoms is fast. The worst symptoms usually manifest after 2 weeks of getting bitten by the tsetse fly. A t.b. rhodesiense may suffer from mental deterioration. If left untreated, it can cause death within a few months.
For patients infected with the t.b. gambiense strain, the progress is slower. The symptoms are mild, and the patient may only suffer from headaches and intermitted fever. After 7 to 14 days, the patient's central nervous system may be affected. The patient may suffer from confusion, daytime sleepiness, and insomnia. Untreated patients may die within three years.
how is t. brucei infection diagnosed? what factors often make diagnosis difficult?
The screening test for the rhodiense strain is done through microscopic examination of fluid samples. The T.b. rhodiense is mostly isolated in the blood, lymph fluid or the biopsy of the skin ulcer. As for the diagnosis of the T.b. gambiense, serologic testing is preferred because it is difficult to detect the parasite in the blood. One of the main factors that affect the diagnosis of the T.b. gambiense strain is the availability of the test kits and serum antibodies for the screening procedure.
