African sleeping sickness, a disease that afflicts sub-Sahara Africa and is fatal in humans without treatment, presents numerous challenges for treatment. It gets its name from one of its symptoms; victims sleep for long periods of time. The tsetse fly, indigenous to parts of Africa, transmits the disease by biting the victim. Identification of the two types of African sleeping sickness, trypanosoma brucei gambiense (T.b.g.) and trypanosoma brucei rhodesiense (T.b.r.), depends on the region of Africa and the type of parasite involved. T.b.g., concentrated in central and west Africa, "represents more than 90 percent of reported cases of sleeping sickness and causes a chronic infection", according to the World Health Organization (WHO). T.b.r., the acute form of African sleeping sickness, comprises less than 10 percent of cases. The basis for effective treatment depends on the form and staging of the disease. During stage one, which has symptoms of itching, fever and joint pain, treatment is more effective and relatively easy to administer. Stage two, however, only responds to medications that can cross the blood-brain barrier; the presence of neurological factors makes this stage more difficult to treat.
Pentamidine
Pentamidine, an antimicrobial medication, only treats the T.b.g. form of African sleeping sickness in the first stage. Administration routes include injection and inhalation. Usage of Pentamidine has undesirable effects that affect several organ systems: cardiovascular (heart and circulation), hepatic (liver), and neurologic (nervous system). Cardiovascular side effects may demonstrate as low blood pressure, severe irregular heartbeats, and heart failure. Hepatic complications, such as an enlarged liver or liver inflammation, may occur with the inhalation route of Pentamidine treatment. Dizziness, confusion, hallucinations and seizures comprise some of the neurological effects.
Suramin
The T.b.r. form is treated with an injectable medication, Suramin, that causes parasites to "lose their energy" and die, according to drugs.com. Suramin only treats the T.b.r. form of African sleeping sickness in its first stage, and like Pentamidine, has several side effects. The more common side effects include diarrhea, headache, irritability, vomiting and various skin sensations. Less common side effects include fatigue, increased photosensitivity (sensitivity to light), swelling, and ulcers or sores in the mouth. Skin changes, such as yellow, pale or clammy skin, loss of consciousness, and convulsions are considered rare side effects of Suramin, according to drugs.com.
Melarsoprol
Both forms of African sleeping sickness in the second stage can be treated with Melarsoprol. Melarsoprol, comprised of arsenic, can cross the blood-brain barrier and kill the parasites. Andrew Jonathan Nok states that "[Melarsoprol] is the only arsenical compound that has shown the remarkable ability to cross the BBB [blood-brain barrier) and kill the CSF [cerebral spinal fluid] residing [parasites]." With the other medications used to treat African sleeping sickness, Melarsoprol has numerous side effects including, encephalopathy (a generalized term for a brain disorder that alters its function), vein inflammation, high blood pressure and joint pain. Due to the possibility of death from Melarsoprol, the risks versus the benefits of this treatment form must be analyzed.
Nifurtimox-Eflornithine Combination Therapy (NECT)
NECT is "the first new treatment in 25 years against Human African trypanosomiasis (HAT) or sleeping sickness," according to "Improved Treatment for Sleeping Sickness Now Available" on Doctorswithoutborders.com. A huge victory for an often neglected disease, NECT simplifies sleeping sickness treatment by using a combination of oral and injectable medications. The benefits of this new treatment, that was accepted to the WHO list of Essential medications in May 2009, according to the Doctors Without Borders website, include ease of administration by health care workers and increased availability to patients afflicted with the disease. This new form of treatment, just as effective as Melarsoprol, eliminates the toxicity, pain and difficulty of administration of Melarsoprol.
References
- World Health Organization:African Trypanosomiasis (Sleeping Sickness)
- Doctors Without Borders:Improved Treatment for Sleeping Sickness Now Available
- Andrew Jonathan Nok:Arsenicals (Melarsoprol), Pentamidine, and Suramin in the Treatment of Human African Trypanosomiasis
- Drugs.com:Suramin (Injection Route)
- University of Virginia Health System:African Trypanosomiasis (African Sleeping Sickness)
