By Holly Nesmith
Common Name: Guinea worm
Genus Species/Etiologic Agent: Dracunculiasis medinensis
Means of Transmission: D. medinensis is transmitted through a cyclical process. Humans drink water that contains small crustaceans, which contain Guinea worm larvae. The larvae are released from the crustaceans upon death; they then enter the abdominal cavity where they mature and mate. The male Guinea worm dies as the females make there way toward the epidermis forming a blister. Water relieves the burning sensation caused by the Guinea worm. When placed in water the female D. medinensis releases her eggs into water sources. Once the larvae are ingested by crustaceans the cycle begins again. These crustaceans are located in still ponds.
Identification: The identification and taxonomy of nematodes is not set in stone. It continually changes and can make classification and identification difficult. The Guinea worm is in Phylum Nematoda. “These helminths are the roundworms, having elongated cylindrical unsegmented bodies, covered in a tough inert cuticle, which may, depending on the species, have striations, lateral spines, terminal expansions or other modifications.” It is part of the superfamily Dracunculoidea. The species in this phylum share some general characteristics in their life cycle. They go through various stages of larvae and are transferred to a host for maturation. There are usually both male and female sexes. The Guinea worm is distinctive because it must be transmitted in fresh water.
Current outbreaks: There is no local incidence rate for the
Guinea worm. It has been largely
eradicated and is now endemic in only twelve countries – all of which are
located in sub-Saharan
History: The Guinea worm is a well documented and
historic disease. It has even been found
in Egyptian tombs. Many scholars believe
it is the fiery serpent referred to in the Old Testament. It traveled from Mesopotamia as most diseases
did along the trade routes and spread across Europe and
Signs and Symptoms: Most infected persons do not demonstrate signs or symptoms until a year following infection – this is usually only noticed once the worm starts to emerge. Inflammation of the area, (redness, swelling, pain, tenderness) skin lesions, and fever are the most common symptoms, which are accompanied by secondary bacterial infections. This period is accompanied by intense many times crippling pain. Many times infection can lead to permanent disabling of the person. D. medinensis most often surfaces from the upper and lower extremities, usually emerging from the hands and feet.
Virulence: The Guinea worm can be considered extremely virulent. Once ingested the larvae adheres to the intestine and moves through the wall into the peritoneal cavity. The first line of defense cells has proven ineffective against the worm, although they are present.
Treatment: The Guinea worm emerges from the skin in a slow and painful process. It is slowly wrapped around a small stick to prevent it from breaking. Wet compresses can be applied to the infected area or medication can be administered to reduce pain. Antibiotics are also an important administered. Although they have no effect on the worm itself, they help to prevent infection of the lesion. These procedures can reduce the amount of time the Guinea worm takes to emerge. “No anti-helminthic medication is effective against the disease, and there is no vaccine.”
Eradication of the Guinea worm is very possible. Since the arthropod vector is known, by
controlling it, the life cycle of the worm can be stopped. The most common means of prevention is
filtering water before drinking. Eradication efforts began in earnest in 1980
through the CDC. Over the years it worked
and convinced the WHO,
Video to Watch
 ANON, Dracunculiasis, 4/14/05, http://www.dpd.cdc.gov/dpdx/HTML/Dracunculiasis.htm, 11/30/06
 Stewart, T., Detailed Taxonomy of the Parasitic Helminths, 10/05/1998, http://www.path.cam.ac.uk/~schisto/Taxonomy/Old.Taxonomy.html ,12/05/06
ANON, Dracunculiasis Eradication Program, 7/3/2005 http://www.who.int/countries/eth/areas/cds/dracunculiasis/en/ ,11/30/06
 ANON, To
The Source: Guinea Worm Eradication in
 ANON, Fact Sheet Dracunculiasis, 10/1/04, http://www.cdc.gov/ncidod/dpd/parasites/dracunculiasis/factsht_dracunculiasis.htm#symptoms, 11/30/06
 Cairncross, S., Muller, R., Zagaria, N., 04/00/2002. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=118073&tools=bot, 12/05/06