What is Sleeping Sickness?
Human African Trypanosomiasis, also known as sleeping sickness or West African Trypanosomiasis, is a parasitic disease that is transferred through bites from certain species of the tsetse fly who have been in contact with already-infected humans or infected animals. This means that sick animals could technically transfer the parasite to humans through the tsetse fly. It is called sleeping sickness because one of the symptoms can be uncontrollable sleepiness.
The parasite lives and reproduces in the bloodstream and tissue fluids of their hosts, and they are particularly good at evading the immune system. Because of this, if it is left untreated sleeping sickness can lead to death.
According to the World Health Organization, there are two types of sleeping sickness, one which is much more common than the other. The most common type of sleeping sickness is Trypanosoma brucei gambiense, which accounts for 98% of cases. This type of sleeping sickness causes a chronic infection, but a person can be affected for weeks or even months without even knowing it. The second type of sleeping sickness is Trypanosoma brucei rhodesiense which accounts for only 2% of the cases.
How common is sleeping sickness?
Sleeping sickness mostly affects people in Sub-Saharan Africa, in rural areas inhabited by the tsetse fly, or, in some cases, when a pregnant woman infected with the parasite passes it on to her unborn child. 70% of cases reported occurred in the Democratic Republic of Congo and cases transferred to the United States are very rare, though it is possible for travellers going to the some of the rural areas of Sub-Saharan Africa to get it.
What are the symptoms?
Symptoms appear in two stages, depending on the level of advancement of the disease.
Stage 1 symptoms:
- Painless skin ulcers
- Swelling of the face or facial edema
- Rashes appearing 6-8 weeks after onset
Stage 2 symptoms:
- Persistent headaches
- Daytime sleepiness and nighttime insomnia
- Behavioral changes or mood swings
- Loss of appetite and weight loss
How is it diagnosed?
Most times, sleeping sickness is not diagnosed until it reaches the second stage. This is because the symptoms in the first stage are nonspecific, which means they could be symptoms of multiple illnesses. For this reason, sleeping sickness is also very difficult to diagnose, especially in areas with unreliable healthcare systems.
Once sleeping sickness is suspected, serological tests are carried out. Serological tests are only available for T. gambiense, so if a patient happens to have T. rhodesiense, it can only be detected at the screening stage through identifying clinical signs such as swollen cervical lymph nodes.
After the parasite is detected, it is necessary to carry out a painful test where the spine is punctured to remove fluids that will determine the stage of the disease.
How is it treated?
Treatment of sleeping sickness depends on the development and stage of the infection. Those people who have infections caught in the first stage are given drugs that lower the toxicity of the parasite. However, when the infection is caught at the second stage, drugs are expensive, and some types found to have worked to some point cause complications.
Researchers are working hard to find a drug that can cure sleeping sickness without uncomfortable or deadly side effects.
Should I be worried?
Unless you live in Sub-Saharan Africa or if you are planning to travel there soon, there is no need to worry about getting sleeping sickness.
Nonetheless, in such a globalized world, it is important to keep an eye out for potential animal-borne disease threats, like sleeping sickness.