Dracunculiasis
Dracunculiasis
Disease History, Characteristics, and Transmission
Introduction
Dracunculiasis, (dra-KUNK-you-LIE-uh-sis) or guinea worm disease, is a preventable helminth (parasitic worm) infection caused by the large female roundworm Dracunculus medinensis. It is endemic in some African countries (including Sudan, Ghana, and Nigeria) within rural communities without safe drinking water
This disease occurs when people drink water contaminated with Dracunculus medinensis larvae. However, symptoms do not usually manifest until about a year after infection. It is at that stage that the female worm ruptures the skin to release larvae, causing severe pain and discomfort to the infected person. There is no treatment for the infection itself except to manually remove the worm.
Disease History, Characteristics, and Transmission
The mode of infection of dracunculiasis was recognized in 1870 when a Russian naturalist noticed the release of larvae from the female worm into a freshwater source. In the 1980s, it was found to be endemic throughout Africa and an eradication initiative was launched.
Symptoms of dracunculiasis do not usually present until around one year after infection, at which time a blister will form at a distal (away from the center) site of the body, such as the lower leg or foot. Some persons may experience allergic-type symptoms such as wheezing, fever, swelling around the eyes, and burning sensations of the skin just prior to lesion formation. After a few days, this blister will burst and the female worm emerges.
Upon making contact with water, the female worm releases millions of larvae that are subsequently ingested by copepods called “water fleas,” where they develop into the infective stage. Human infection occurs by drinking contaminated water. The water flea is digested, but the larvae survive, migrate to the small intestine, mate, and the females mature to adult size of up to 39 inches (100 cm). The female then migrates to the distal site and the process repeats.
WORDS TO KNOW
DISTAL: Distal comes from the same root word as “distant,” and is the medical word for distant from some agreed-on point of reference. For example, the hand is at the distal end of the arm from the trunk.
HELMINTH: A representative of various phyla of worm-like animals.
POTABLE: Water that can is clean enough to drink safely is potable water.
Scope and Distribution
The people most commonly affected by dracunculiasis are those living in rural communities without established water treatment facilities. Due to the mode of transmission, males and females of all ages are vulnerable to infection if exposed to a contaminated water source. In some endemic areas, over half of the infected individuals are children, as they are they main water carriers.
Following eradication efforts, by 2006, the occurrence of dracunculiasis was mostly restricted to remote rural villages in only 12 countries of sub-Saharan Africa. Over half of these cases had been reported from Sudan, where ongoing war conditions made it difficult to successfully eradicate the disease.
Sporadic cases of dracunculiasis have been noted in America and Australia among African immigrants.
Treatment and Prevention
Treatment for dracunculiasis is limited and there is no definitive medication available to eliminate or prevent infection. The most common method for removing the worm once it has immerged is to gently pull it out a few inches each day. This slow process allows for the complete removal of the worm. This process may only take a few days, but generally takes weeks. Analgesics may also be used to reduce swelling and help with pain management.
As dracunculiasis is transmitted only by drinking contaminated water, disease prevention is possible by implementing simple measures. Ensuring the maintenance of a water source free from contamination is vital and the filtration of water prior to drinking would be further beneficial. Prevention is most often accomplished by either treating ponds with insecticide that kills the copepods that host the larvae while still leaving the water potable, or by filtering untreated water before it is consumed. Both methods break the chain of transmission. It is also essential to prevent people with open guinea worm wounds from swimming or bathing in shared water facilities used for drinking.
Impacts and Issues
Although the mortality rate for dracunculiasis is very low, morbidity is a major concern as the disease often affects entire communities and proves to be a heavy social and economic burden. Persons are often bedridden for some time during and following the emergence of the worm and as such, are unable to contribute to the work within the community. The seasonality of outbreaks further highlights the impact of disease whereby emergence often occurs during the peak of the agricultural year, often at harvest time, when the loss of labor is most damaging.
Children of parents infected with dracunculiasis are more likely to suffer from malnutrition than children of uninfected families. With an incapacitated parent, children are often required to assume adult roles within the family that, as a result, may also affect their chances of gaining an education. It is the culmination of these nutritional, social, economic, and educational factors, along with the practicality of possible prevention measures, that has made world health authorities identify dracunculiasis a candidate for eradication.
Former United States President Jimmy Carter has led a campaign to eliminate guinea worm disease for more than twenty years. Working in conjunction with the Centers for Disease Control and Prevention (CDC) and others, if successful, the Carter campaign will result in the first eradication of an infectious disease since smallpox. Before the campaign, there were between three and five million cases occurring per year and the disease was endemic throughout Africa and areas of Asia.By 1996, the number of worldwide cases had been reduced to around 150,000. By 2006, cases of reported guinea worm disease decreased to about 12,000, the disease was eliminated from Asia, and remained endemic in only about nine African countries.
IN CONTEXT: ERADICATION PROGRAM EFFECTIVENESS
Since the implementation of the eradication program in the 1980s, the global prevalence of dracunculiasis has drastically decreased. While in 1986, an estimated 3.5 million people were suffering from the disease worldwide, only 32,193 cases were reported in 2003, a decrease of over ninety percent.
SOURCE: World Health Organization (WHO)
See AlsoHelminth Disease; Roundworm (Ascariasis) Infection; Sanitation; Vector-borne Disease; War and Infectious Disease; Water-borne Disease.
BIBLIOGRAPHY
Books
Mandell, G.L., Bennett, J.E., and Dolin, R. Principles and Practice of Infectious Diseases. Vol. 2. Philadelphia, PA: Elsevier, 2005.
Periodicals
Cairncross, S., Muller, R., and Zagaria, N. “Dracunculiasis (Guinea Worm Disease) and the Eradication Initiative.” Clinical Microbiology Reviews. 15, 2 (2002): 223–246.
Hopkins, D.R., Ruiz-Tiben, E., Downs, P., Withers, P.C., and Maguire, J.H. “Dracunculiasis Eradication: The Final Inch.” The American Journal of Tropical Medicine and Hygiene. 73, 4 (2005): 669–675.
Web Sites
Directors of Health Promotion and Education. “Guinea Worm Disease.” 2005 <http://www.dhpe.org/infect/guinea.html> (accessed Feb. 22, 2007).
World Health Organization (WHO). “Dracunculiasis eradication.” 2007 <http://www.who.int/dracunculiasis/en/> (accessed Feb. 22, 2007).