Parasite.

The World Health Organization (WHO) currently targets dracunculiasis, also known as Guinea Worm disease (GWD), for eradication. Although the disease displays low mortality rates, it has a high morbidity level that commonly leads to disability. GWD is primarily located in remote, rural villages in sub-Saharan African countries that lack access to safe drinking water. After imbibing water containing Dracunculiasis medinensis-infected water fleas (copepods), these intermediate hosts are killed by the stomach’s digestive juices, releasing the larvae into the small intestine. The larvae mature into female adult worms in a process that takes about one year. The worms then emerge under the skin usually in the lower extremities, causing painful ulcers along with symptoms of fever, nausea, vomiting, diarrhea, and dizziness. Often the infected individuals submerge the ulcerated area in water, which triggers the emerging worm to release larvae into the water source. The released larvae are then ingested by the copepods, thus continuing the life cycle.1

Life Cycle of D. medinensis. By courtesy of Advances in Parasitology Vol.61, ©2006.

The adult worms can be up to 1 meter long and take several weeks to extract, in a process that involves winding a few centimeters of the worm around a stick every day. The painful ulcers often render the individual disabled and unable to walk until the worm is extracted. There is no antihelminthic medication or vaccine against the disease, so prevention is currently the sole intervention technique to reduce GWD prevalence.1

Foot blister induced by the female guinea worm in a person with dracunculiasis (guinea worm disease). By courtesy of the Canadian Medical Association Journal, ©2004.

Ulcer with D. medinensis emerged and being manually extracted. By courtesy of Advances in Parasitology Vol.61, ©2006.

For more information, see previous projects on Dracunculiasis:

http://www.stanford.edu/class/humbio103/ParaSites2006/Dracunculiasis/Index.htm

http://www.stanford.edu/class/humbio103/ParaSites2005/Dracunculiasis/index.htm

http://www.stanford.edu/class/humbio103/ParaSites2004/Dracunuliasis/Guinea%20Worm.html

http://www.stanford.edu/class/humbio103/ParaSites2003/Dracunculiasis/Index.html

http://www.stanford.edu/class/humbio103/ParaSites2001/dracunculiasis/DRACUNCULIASIS.html

 


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