Epidemiology
Sleeping sickness, or African trypanosomiasis, is caused by a protozoan of the genus Trypanosoma.
It is transmitted to humans by the bite of a fly: the tsetse fly or glossina (of the genus Glossina) previously infected from a human or from animal carriers with the pathogenic parasite.
This fly bites very early in the morning or late in the evening, and its bite is painful. It is found mainly in the vegetation on the edge of waterways and lakes, forests and vast expanses of shrubby savannah.
The disease is present in Sub-Saharan Africa.
Symptoms
There are 2 forms of the disease, depending on the species of trypanosoma that is responsible for the disease:
- Trypanosomiasis due to Trypanosoma brucei gambiense (T.b.gambiense)
- in Central and Western Africa, with slow progression, sometimes with periods of remission. It can go without symptoms for a very long time.
- Trypanosomiasis due to Trypanosoma brucei rhodesiense (T.b.rhodesiense)
- in Eastern and Southern Africa; it progresses much more quickly, and without periods of remission.
Following penetration of the skin, trypanosoma multiply locally before spreading in the blood and the central nervous system. In the case of T.b.gambiense progression can take years.
Incubation is generally 2 to 3 weeks, but can be longer (several months or years). It is silent or marked by a lesion resembling a boil, which can easily go unnoticed on darkly pigmented skin.
In the most typical cases, the disease starts with bouts of fever accompanied by headaches, joint pain, pruritis, palpable ganglions and oedema. Then, when the parasite invades the central nervous system, neurological signs appear leading to a state of confusion, sensory disorders and coordination problems, nighttime restlessness and daytime drowsiness.
Sleep disorders, which are the source of the disease's name, are an important characteristic of the second phase of the disease. In the absence of treatment, the outcome is always fatal.
Treatment
The treatment of sleeping sickness to be administered depends on the stage of the disease. The earlier the diagnosis, the better the chances of recovery. Treatment must be performed in a hospital setting.
- First stage: Pentamine, Suramine.
- Second stage: Melarsoprol, Eflornithine.
Prevention
1. Vaccination
There is no vaccine.
2. Prevention of insect bites
As with mosquitoes, prevention is mainly based on :
- wearing ample clothing that covers the body,
- use of appropriate repellent products for the body and insecticide for clothing (Moustifluid High Protection Tropical Zones and Moustifluid Lotion For Fabrics and Clothing Tropical Zones)
- and repellent-sprayed mosquito nets (Moustifluid Lotion For Fabrics and Clothing Tropical Zones).
There is another human form of trypanosomiasis that affects South Africa: American human trypanosomiasis, or Chagas disease. It is caused by a parasite belonging to a different species (Trypanosoma cruzi) and is transmitted by small insects called reduviid bugs.