Dr. D. Scott Smith
Human Biology 103
Today, dracunculiasis, more commonly known as Guinea Worm Disease, is only found in 13 countries in sub-Saharan Africa. It is caused by a nematode, or flatworm, Dracunculus medinensis, which infects small Crustaceans, called Cyclops which dwell in water supplies. Human because infected if they drink from an unfiltered water supply, which contains infected water fleas.
As the World Health Organization states, although dracunculiasis is not a cause of mortality, "it is a real burden in terms of morbidity, incapacity and suffering for those affected1." Those infected by the disease are most often rural farm workers, who, after contracting the disease, are often not able to work or take care of their children for months.
As will be explained further, eradication of the disease is relatively simple and is in near sight--eradication can be accomplished simply by preventing people from drinking from water contaminated by the parasite.
After Small Pox, Guinea Worm Disease will be the second disease to be eliminated from the world2.
Means of Human Infection
Location of Larvae in Humans
Location of Adults in Humans
Ingestion of larvae in infected copepods (Cyclops and others)
Intestinal tract, deep connective tissue
Deep connective tissues, subcutaneous tissue, dermis
Pruritus, blister, ulcer, eosinophilia, secondary infection
Adult worm in lesion, larvae from worm in ulcer
*Table taken from page 354 of Markell and Voge's Medical Parasitology by Edward K. Markell, Ph.D., M.D.
Dracunculus medinensis (tissue nematode)
Guinea Worm Disease
Adult female worms can measure up to one metre in length and 2mm across3. Less conspicuous male worms average only 2cm long4.
No known animal reservoirs.
Cyclops--small (.5-2 mm) Crustacean
HISTORY OF DISCOVERY:
Dracunculiasis is documented as early as the 15th century BC in Egypt. A description of the disease is found in the "Turin Papyrus," which describes the ancient myth of the Egyptian sun god. This documentation was recently supported by the pathological examination of an Egyptian mummy in which a calcified worm was identified as Dracunculus medinensis5. Similar documentation, dating back to 11th century AD, has also been found in Persia and Israel.
It wasn't until the 18th century that that Swedish naturalist Carolus Linnaeus first suggested that the "fiery serpents" plaguing Middle Eastern countries were a type of parasitic worm. Finally, in 1870, Alexei P. Fedchenko discovered the life cycle of the Guinea Worm and the intermediate host--the Cyclops.
Beginning in the early 1920's, world-wide eradication programs were first implemented which focused on water sanitation in an effort to eliminate the Cyclops and therefore dracunculiasis from public water supplies. These efforts have continued throughout the 20th and 21st centuries. In 1980, one of the goals set for the International Water Supply and Sanitation Decade (1981-1990), by the World Health Organization in collaboration with the United Nations, was the eradication of dracunculiasis6. Finally, as states on the website for the Center for Disease Control, "In May 1991 the Forty-fourth World Health Assembly endorsed the goal of eradicating dracunculiasis (guinea worm disease) by the end of 1995 (resolution WHA44.5)7." This goal has been reached in numerous areas of the world, including Pakistan (last case reported in 1993), Iran (last case reported in the mid-1970's), and India (last case reported in 1997)8. All current endemic areas are in sub-Saharan Africa.
Symptoms include pain in joints, nausea, fever, pruritus, blisters, ulcers, eosinophilia, and secondary infections9. In the best case scenario, after extraction of the worm, the patient may only be disabled for 2-4 weeks. However, more often than not, the patient remains incapacitated for several months, due to the presence of multiple worms, the sensitivity of areas of the body which worms migrate to and through (such as the soles of the feet) and serious secondary bacterial infections11. The is no way to guarantee immunity.
People in remote, rural communities are most commonly affected by Guinea worm disease. These patients most often do not have access to medical care. Ulcers may therefore take many weeks (8 weeks average) to heal and often become infected, causing complications such as locked joints or even permanent crippling. Each time a worm emerges, persons are often unable to work and 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 Guinea worm disease cannot care for their children. They also cannot tend or harvest or crops, which leads to financial problems for the entire family.
As described by the Carter Center, on their website:
In Cyclops: After the Cyclops swallows the embryonic parasite, it takes approximately two weeks for the parasite to puncture the digestive tract, make its way to the abdomen, and develop into an infectious larvae. 1-3 weeks after the larvae reaches the infectious stage, the Cyclops, which can no longer swim, sinks to the bottom of the water supply and dies12.
In Humans: Symptoms of the disease start to appear one year after a human drinks water containing an infected Cyclops, when the full-grown female worm starts to make its way through the body13.
The only way to diagnose this disease is to locate an adult worm in the lesion, or larvae from the adult female worm in the ulcer14.
MANAGEMENT AND THERAPY:
There are no drugs to combat or vaccinate against the parasite, nor are there any drugs, besides pain reduces, to treat any of the clinical symptoms.
Valiant world-wide eradication efforts have decreased the number of cases of Dracunculiasis from 3.2 million cases in 1986 to less than 75,000 in 2000, as stated in a news release issued by the Carter Center on May 21, 200115. All remaining endemic areas are found in 13 countries in sub-Saharan Africa.
73% of all reported cases are found in Sudan: "In 2000, The Sudan Guinea Worm Eradication Program (SGWEP) reported more than 54,000 new cases of Guinea worm disease (actual number of cases in Sudan is unknown) from 3,386 villages16."
PUBLIC HEALTH AND PREVENTION:
A program to eliminate Guinea Worm disease from Sudan (the area with the highest rate of infection) was recently describes in a news release issued by the Carter Center on May 21, 2001. Organizations such as the Carter Center, Health and Development International (HDI), Hydro Polymers of Norsk Hydro, and Norwegian Church Aid (NCA), has begun to distribute 9 million pipe filters--one for every man, woman and child at risk of this disease17. The pipe filters can we worn around the neck, in case residents have to quickly flee as a result of war, which has plagued the country for the past 20 years.
4Markell, Edward. Medical Parasitology. Philadelphia: W.B. Saunders Company, 1999: 337.
9Markell, Edward. Medical Parasitology. Philadelphia: W.B. Saunders Company, 1999: 354.
13Markell, Edward. Medical Parasitology. Philadelphia: W.B. Saunders Company, 1999: 354.