Thursday, December 17, 2009

What is dracunculiasis?


Definition

Dracunculiasis, or guinea worm disease (GWD), is caused by
the parasitic guinea worm, a long, thin worm that can grow inside humans.
Dracunculiasis affects people living in certain parts of rural Africa who drink
water contaminated by guinea worm larvae. GWD is one of the few diseases
specifically mentioned in the Bible, where it is called dracunculiasis
medinensis
, or “fiery serpents.” An adult female worm can reach up to
three feet long.













Causes

People get dracunculiasis by drinking contaminated water infested with water fleas
that have ingested the guinea worm larvae. The guinea worms, usually female, move
through the body, and about one year later, protrude through the skin, usually on
the lower leg or feet, causing immense pain. At the site of protrusion, there is a
blister or an ulcer, and the worm can be seen emerging. Some people seek
relief by placing the infected area in open water (such as a pond, lake, or river)
that is used for drinking, which allows the female worms to release larvae into
the water and repeat the process of infestation.




Risk Factors

This disease tends to affect people living in rural or poorer communities in certain countries in Africa, where water sources are scarce and where drinking water most often comes from open, and exposed,sources.




Symptoms

Symptoms do not appear until about one year after a person has become infected
with dracunculiasis. When the guinea worm prepares to emerge from the
body, a person usually experiences intense pain and itching or burning, often
followed by nausea, vomiting, and fever. A blister forms at the site of where the
worm will emerge, leaving the person virtually incapacitated, sometimes for many
months, as the worm is gently pulled from the body and removed.




Screening and Diagnosis

There is no screening for dracunculiasis. A person does not know he or she has the disease until the worm begins to exit the body, about one year after contaminated water has been ingested.




Treatment and Therapy

Once the worm emerges at the site of the blister, it is pulled out in a slow and painful process; the infection is then cleaned. The only treatment for the infection is to help alleviate symptoms once the worm emerges.




Prevention and Outcomes

Preventive methods against dracunculiasis include using a cloth filter to remove water fleas from drinking water and to drink water from protected (closed) sources. Persons already infected with a dracunculiasis blister should not enter any water source that is used for drinking.


Although this disease was once widespread throughout Asia and Africa, public health experts and others are getting closer to eradicating the disease, aided by disease education and the use of chemicals to treat potentially unsafe drinking water.




Bibliography


Berger, Stephen A., and John S. Marr. Human Parasitic Diseases Sourcebook. Sudbury, Mass.: Jones and Bartlett, 2006.



Centers for Disease Control and Prevention. “Progress Toward Global Eradication of Dracunculiasis, January, 2008-June, 2009.” Morbidity and Mortality Weekly Report 58, no. 40 (2009): 1123-1125.



Muller, Ralph. Worms and Human Disease. 2d ed. New York: CABI, 2002.



Parker, James N., and Philip M. Parker, eds. The Official Patient’s Sourcebook on Dracunculiasis: A Revised and Updated Directory for the Internet Age. San Diego, Calif.: Icon Health, 2002.



Roberts, Larry S., and John Janovy, Jr. Gerald D. Schmidt and Larry S. Roberts’ Foundations of Parasitology. 8th ed. Boston: McGraw-Hill, 2009.



Weedon, David. Skin Pathology. 3d ed. New York: Churchill Livingstone/Elsevier, 2010.

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