African typanosomiasis, or sleeping sickness, is a disease caused by a protozoan parasite. It is transmitted to humans through tsetse flies. This disease usually starts with fever and after that causes progressive nervous system damage. Treatment to this disease is usually complicated by the serious side effects of the drugs. Parasites that cause this disease are T. brucei rhodesiense (East African) and T. brucei gambiense (West African)
How sleeping sickness is transmitted?
This is a tropical disease transmitted by the tsetse flies of the genus Glossina. This fly acquires the infection by sucking blood from an infected person. Then the parasite travels into the gut of the fly. Here, it gets multiplied and transmitted into the salivary glands of the fly. When the fly takes another blood meal, parasites are transmitted into a new host.
What are the symptoms of sleeping sickness?
Usually after a bite, an inflammatory scar is developed. It is called trypanosomal chancre. It appears usually one or two weeks after the bite. Then the parasite starts to disseminate throughout the body. This results in an illness characterized by fever and malaise.
The fever is characterized by intermittent bouts of high fever lasting for several days. In between episodes the patient is usually not having fever. Other symptoms of this disease can be classified as stages 1 and 2.
What is the stage 1 disease?
Stage 1 disease is characterized by widespread lymph node enlargement and an enlarged spleen. In addition, stage 1 disease can cause anemia, increased white cell count, and reduced platelet counts.
Lymph node enlargement is characterized by non-painful, rubbery and discrete lymph nodes. Usually lymph nodes in the neck are involved.
In addition, patients with stage 1 sleeping sickness may develop itchiness and rashes. Rarely, patients with stage 1 sleeping sickness can get headache, joint pains, weight loss, edema, liver enlargement, and increased heart rate.
Some people in this stage can get inflammation of the heart or myocarditis. This complication can cause heart failure.
What are the symptoms of stage 2 disease?
Stage 2 illness is characterized by the involvement of central nervous system. Here, the patient gets day time sleepiness. In addition, patients with stage 2 sleeping sickness develop restlessness and insomnia in the night.
In addition, various movement problems may develop in this stage. They are characterized by involuntary dancing-like movements, tremors, and difficulty in walking. In this stage, patients’ symptoms may resemble Parkinson’s disease.
What are the important differences between two species?
Usually untreated T. b. rhodesiense infection can cause death in weeks to months. In addition, patients usually get ill quickly. Travelers will get the fever and other symptoms of stage 1 disease before the end of the trip. However, disease caused by the other parasite (T. b. gambiense) can go into months and years.
How sleeping sickness is treated?
The medications used for treatment of sleeping sickness are suramin, pentamidine, eflornithine, and the organic arsenical melarsoprol. These drugs are quite toxic and administration should be done by a specialist. The most common side effect of these drugs is renal failure.
Summary
If not treated, sleeping sickness or African trypanosomiasis can be lethal. Main symptoms are fever, lymph node enlargement, spleen enlargement and increased heart rate. However, it is usually treated with quite toxic medications. Usually the disease can be prevented by avoiding areas of infection, by wearing protective clothing, and by using insect repellents.
Sources:
Harrison’s principles of internal medicine. (17th ed.)
Welburn SC et al: Crisis, what crisis? Control of Rhodesian sleeping sickness. Trends Parasitol 22:123, 2006 [PMID: 16458071]
