The clinical signs and symptoms of human African trypanosomiasis are nonspecific as they tend to occur in several other infectious ailments. Hence, the use of diagnostic laboratory examinations is essential to confirm the diagnosis. For example, it is possible to obtain a biopsy of the skin lesions or chancres which develop at the site where the tsetse fly has bitten the patient. The biopsy may identify the parasite upon microscopic examination (Centers for Disease Control, 2010).
The physician can also identify the parasites with a biopsy of a lymph node as the fluid therein may contain the microorganism. Moreover, a microscopic smear of the patient’s blood with the proper stain may identify the presence of parasites and thus confirm the diagnosis. When laboratory staff centrifuge or spin the blood of these patients, the parasites tend to accumulate just above the layer of white blood cells.
Therefore, an examination of the buffy coat is a reasonable approach to look for the trypanosomes whether Trypanosoma brucei rhodesiense or Trypanosoma brucei gambiense. One of the best ways, however, to identify the parasite with microscopic examination is with a fresh wet mount because the parasites are motile and attract the attention of the viewer. They will remain motile for a few hours, and the laboratory staff or physician must look at the slide promptly.
Serologic tests may be helpful to identify this condition; however, some of them are not available in the United States. Furthermore, they may not be sensitive for Trypanosoma brucei rhodesiense infection.
Diagnostic Lumbar Puncture
Every patient who has African trypanosomiasis must undergo a lumbar puncture. This is especially useful to detect the second stage of the disease in which there is parasitic invasion of the central nervous system. Elevation of protein in the cerebrospinal fluid and a white cell count of at least six are indicative of the disease in light of a clinical history and physical examination which are suggestive of this medical condition.
There may also be trypanosomes which appear on microscopic view of the cerebrospinal fluid. Additionally, immunoglobulin M (IgM) may become elevated in the cerebrospinal fluid as well. Nevertheless, the physician who performs the spinal tap should always submit the fluid to the clinical laboratory for a variety of routine tests to search for other diagnostic possibilities.
The lumbar puncture is essential because it may delineate whether the patient has first or second stage African trypanosomiasis. The treatment of this infection depends not only on which parasite is responsible, but also on the stage of illness.
Two-Year Office Follow-up
No specific test is available to document a microbiologic cure in these patients; however, drug therapy with antitrypanosomal medication should lead to microbiologic cure. Consequently, patients with African trypanosomiasis require office visits and follow-up for two years after they have completed treatment. The visits must take place every six months, and a lumbar puncture on each visit is the recommendation.
If the patient experiences any signs or symptoms after the completion of treatment, visits to the health care facility should be more frequent than six month intervals.
Sources
- Centers for Disease Control. (2010). Parasites—African trypanosomiasis (also known as sleeping sickness) Retrieved January 19, 2012.
- World Health Organization. (2012). African trypanosomiasis (sleeping sickness). Fact sheet. Retrieved January 19, 2012.
Disclaimer: The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact their physician for advice.
Michael Koger - Dr. Koger obtained his medical education at Meharry Medical College and specialized in Internal Medicine.
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