Dracunculiasis, more commonly known as Guinea Worm Disease (GWD), is a preventable infection caused by the parasite Dracunculus medinensis. The word Dracunculus comes from the Latin "little dragon".
Life cycle
Adult female Dracunculus worms emerge from the skin of infected persons annually. Persons with worms protruding through the skin may enter sources of drinking water and unwittingly allow the worm to release larvae into the water. These larvae are ingested by fresh water copepods ("water fleas") where these develop into the infective stage in 10-14 days. Persons become infected by drinking water containing the water fleas harboring the infective stage larvae of Dracunculus medinensis.
Once inside the body, the stomach acid digests the water flea, but not the Guinea Worm. These larvae find their way to the small intestine, where they penetrate the wall of the intestine and pass into the body cavity. During the next 10-14 months, the female Guinea Worm grows to a full size adult 60‑100 centimeters (2‑3 feet) long and as wide as a cooked spaghetti noodle, and migrates to the site where she will emerge, usually the lower limbs.
A blister develops on the skin at the site where the worm will emerge. This blister causes a very painful burning sensation and it will eventually (within 24 to 72 hours) rupture. For relief, persons will immerse the affected limb into water, or may just walk in to fetch water. When someone with a Guinea Worm ulcer enters the water, the adult female releases a milky white liquid containing millions of immature larvae into the water, thus contaminating the water supply. For several days after it has emerged from the ulcer, the female Guinea Worm is capable of releasing more larvae whenever it comes in contact with water.
Symptoms
Infected persons do not usually have symptoms until about 1 year after they become infected. A few days to hours before the worm emerges, the person may develop a fever, swelling and pain in the area. More than 90% of the worms appear on the legs and feet, but may occur anywhere on the body.
People, in remote, rural communities who are most commonly affected by GWD do not have access to medical care. Almost invariably the skin lesions caused by the worm develop secondary bacterial infections, which exacerbate the pain, and extend the period of incapacitation to weeks or months-causing in some cases disabling complications, such as locked joints and even permanent crippling. Each time a Guinea worm emerges, persons may be unable to work or resume daily activities for an average of 3 months. This usually occurs during planting or harvesting season, resulting in heavy crop losses. Parents who have active GWD may not be able to care for their children. They also cannot tend or harvest or crops, which leads to financial problems for the entire family.
Treatment
Once the worm emerges from the wound, it can only be pulled out a few centimeters each day and wrapped around a small stick. Sometimes the worm can be pulled out completely within a few days, but this process usually takes weeks or months.
In the Middle East, it is customary to remove it by wrapping the protruding end of it around a stick and slowly turning the stick, twisting the worm around the stick. There is speculation that the serpent on the end of Moses's stick in the Biblical story was really one of these parasites.
No medication is available to end or prevent infection. However, the worm can be surgically removed before an ulcer forms. Analgesics, such as aspirin or ibuprofen, can help reduce swelling; antibiotic ointment can help prevent bacterial infections.
Affected countries
Dracunculiasis now occurs only in 12 countries in sub-Saharan Africa. Transmission of the disease is most common in very remote rural villages and in areas visited by nomadic groups. In the 2nd century BC, the Greek writer Agatharchides described this affliction as being endemic amongst certain nomads in what is now Sudan and along the Red Sea (fragments preserved in Photius, Bibliotheca Cod. 250.59, 453b; and Plutarch, Quaestiones Convivales 8.9.16).
In 2003 the three most endemic countries — i.e. Sudan, Ghana, and Nigeria — reported 20,299; 8,290; and 1,459 cases of GWD respectively. Other endemic countries reporting cases of GWD in 2003 were: Benin (30 cases), Burkina Faso (203 cases), Côte d'Ivoire (42 cases), Ethiopia (28 cases), Mali (829 cases), Mauritania (13 cases), Niger (293 cases), Togo (669 cases), and Uganda (26 cases).
GWD-free countries
Asia is now free of the disease. Transmission of GWD no longer occurs in several African countries, including Kenya, Senegal, Cameroon, Chad, and Central African Republic. No locally acquired cases of disease have been reported in these countries in the last year or more. The World Health Organization has certified 168 countries free of transmission of Dracunculiasis, including four formerly endemic countries: Pakistan (in 1996), India (2000), and in Senegal and Yemen (in 2004).
Prevention
Because GWD can only be transmitted via drinking contaminated water, educating people to follow these simple control measures can completely prevent illness and eliminate transmission of the disease:
- Drink only water from underground sources (such as from borehole or hand-dug wells) free from contamination.
- Prevent persons with an open Guinea Worm ulcer from entering ponds and wells used for drinking water.
- Always filter drinking water, using a cloth filter, to remove the water fleas.
- Additionally, unsafe sources of drinking water can be treated with an approved larvicide , such as ABATE®* , that kills water fleas, and communities can be provided with new safe sources of drinking water, or have existing dysfunctional ones repaired.
See also
Resources
Last updated: 10-29-2005 02:13:46
