Sleeping sicknessFabian Dupont is a freelance writer in the NetDoktor medical editorial team. The human physician is already for scientific work among other things Belgium, Spain, Rwanda, the USA, Great Britain, South Africa, New Zealand and Switzerland. His doctoral thesis focused on tropical neurology, but he is particularly interested in international health science (public health) and the comprehensible communication of medical ies.
The African sleeping sickness is a tropical disease, which is caused by parasites. These are transmitted by the bite of the tsetse fly. Sleeping sickness only exists in Africa, but related diseases also occur on other continents. It is mainly locals who contract the disease, while tourists rarely do so. Untreated, sleeping sickness is usually fatal. Read more about the African Sleeping sickness.
Sleeping sickness: description
Sleeping sickness (trypanosomiasis) is caused by the unicellular parasite Trypanosoma brucei. There are two forms of the disease – the West African and the East African variants:
– The East African form accounts for only about two percent of all cases of sleeping sickness. It progresses very quickly. This means that there is very little time for diagnosis and therapy. However, this form of sleeping sickness mainly affects animals and rarely humans. – The West African form of sleeping sickness is more common, progresses more slowly, and is sometimes diagnosed years after infection.
The geographical boundaries between the two forms of the disease are becoming increasingly blurred. For example, in Uganda, an East African country, both forms are already present in different areas. Even if the data situation is difficult to survey, the Democratic Republic of Congo and the Central African Republic are particularly affected by the tropical disease. Since the data come from different health care systems, it can be amed that sleeping sickness is also found in other countries in this region.
The pathogen: trypanosomes
Trypanosomes belong to the protozoa as, for example, the causative agent of malaria. Like malaria, sleeping sickness cannot be transmitted from person to person. The pathogens of the disease are transmitted to humans by the bloodsucking tsetse fly when it bites.
The West and Central African variant of sleeping sickness is caused by the subspecies Trypanosoma brucei gambiense, while the East African variant is caused by Trypanosoma brucei rhodesiense.
Sleeping sickness: symptoms
After the bite of a tsetse fly and the transmission of the trypanosomes, a painful, inflamed redness can develop at the bite site within one to three weeks (subspecies rhodensiense) or weeks to months (subspecies gambiense). Physicians speak of a so-called Trypanosome chancroid. The injection site is often in the face or neck area. Disease spreads the parasites through the blood-. Lymphatic pathway throughout the body from. Lymph nodes swell severely, and periodic episodes of fever occur. Severe headache, pain in the limbs, chills and fatigue are also possible. If the kidneys are also affected, nephritis can be the result.
Finally, the trypanosomes infect the central nervous system (meningoencephalic stage). As a result, the sleep-wake cycle disorders that give the disease its name occur. In addition, paralysis, convulsions or Parkinson's-like symptoms (rigor = muscle rigidity, tremor = trembling, ataxia = disturbed coordination of movement) can occur. Behavioral disturbances and irritability also present themselves. Eventually, the patient falls into a coma and dies.
This general course of the disease is seen in both forms of sleeping sickness. In detail, however, there are some differences:
West African sleeping sickness
In the West African sleeping sickness (pathogen: Trypanosoma brucei gambiense), the course of the disease is slower than in the East African form. It can take up to three weeks for skin changes to appear at the injection site. The feeling of fatigue may last for several months before the actual symptoms of sleeping sickness appear. Personality changes appear after months to years. The patient is easily irritable. He complains of increased fatigue. The distortion of the day-night rhythm often occurs slowly over several months. The feeling of hunger is disturbed and the patients lose weight. After a few years, the affected person falls into a coma. Eventually die of multiple organ failure. The East African sleeping sickness (pathogen: Trypanosoma brucei rhodesiense) is basically a rapid infection. More serious variant of the more common West African form. Fever and chills, as well as a painful, inflamed bite site, can appear days to weeks after the tsetse fly bites. The parasites quickly infect the lymphatic and blood systems and spread throughout the body. Swelling of the lymph nodes, liver and spleen can be felt after only a few weeks. Irritability, sleep disturbances and paralysis can occur after weeks to months. After a few months, the patient falls into a coma. Dies of multiple organ failure.
Sleeping sickness: causes and risk factors
Sleeping sickness is caused by the parasite (protozoan) Trypanosoma brucei, and there are two subspecies: T. b. rhodesiense et al. b. gambiense. Transmitted by the bites of the blood-sucking tsetse fly from either infected animals (subspecies rhodesiense) or infected humans (subspecies gambiense) to healthy humans.
Blood-sucking exposes the sleeping sickness pathogen from the tsetse fly to human skin. Spreads throughout the body via the lymphatic system and bloodstream and eventually affects the central nervous system.
Because trypanosomes periodically change their surface, they are not recognized quickly enough by the immune system. This so-called antigenic switch explains why the human immune system is so helpless against sleeping sickness.