AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Dracunculiasis is an infection caused by the nematode Dracunculus medinensis, also known as the guinea fire worm. D medinensis is in the order Spirurida, an order of parasites that includes the filariae Wuchereria bancrofti, Brugia malayi, and Loa loa. During the last 25 years, concerted efforts to eradicate the guinea worm have been undertaken and these have resulted in a reduction of more than 99% of worldwide cases of dracunculiasis.

Current disease incidence is low and is limited specifically to sub-Saharan Africa. The Centers for Disease Control and Prevention (CDC) proposed a global campaign for eradication of dracunculiasis in 1980, and, in 1988, a number of African ministers of health set a target date of 1995 for total eradication. Although several factors have prevented accomplishment of this goal, the CDC now projects that the disease may be completely eliminated by 2009. This will mark an important epidemiologic medical accomplishment, as well as the end of a fascinating organism.

During ancient times, the presence of dracunculiasis can be inferred by the universally recognized symbol of medicine, the Greek asklepios (ie, Roman aesculapius), which consists of a one-headed snake wrapped around a stick. Dead female worms have also been found in Egyptian mummies older than 3000 years, and writings in ancient Sanskrit, Greek, and Hebrew refer to Dracunculus infection. To this day, the most effective method dracunculiasis treatment involves extraction by wrapping the worm around a stick. The term dracunculus is Latin for "little dragon," a misnomer and reference to the symbol. Thus, when the guinea worm disappears, one of the original inspirations for the discipline of medicine will also disappear. Currently, the infection persists and, although uncommon, can cause significant morbidity.

Pathophysiology

Ingestion of water that contains infective Dracunculus larvae causes the infection. The larvae reside in an intermediate host, a tiny fresh-water crustacean or copepod of the genus Cyclops. The acidic environment of the stomach and duodenum kills the copepods. The larvae are subsequently released in the stomach or small intestine and penetrate the mucosa to mate and mature in the abdomen or retroperitoneal space approximately 60-90 days after initial infection. The maturation stage can last for up to 1 year, and, during this time, the adult male probably dies because only the female worm is recovered from symptomatic patients.

After maturation is complete, the female Dracunculus reaches a length of up to 1 m (with a thickness of only 1-2 mm) and slowly migrates from the GI tract into subcutaneous tissue, usually to a location in the lower extremity. The actual route of migration is unknown. In this subcutaneous location, one or more females prepare larval exit sites through the skin, from whence larvae may be released into another water supply. Free-living larvae can survive only 3 days without a host; they become infective after 2 weeks (2 molts) within the host copepod.

Frequency

United States

Dracunculiasis is rarely imported to the United States. Two cases have been reported since 1995, both occurring in individuals from Sudan.

International

In the early 1990s, 3-5 million cases of dracunculiasis occurred worldwide each year. By 1996, only 152,805 cases were reported, most from Ghana and Sudan. Presently, only 9 countries are endemic: Sudan, Ghana, Nigeria, Mali, Togo, Burkina Faso, Ethiopia, Niger, and Ivory Coast. Recent statistics indicate that only 8,191 cases were reported during the first half of 2005 from these 9 nations. At the end of 2004, all of Asia was free of the disease. Sporadic cases have been noted in Australia and North America in African immigrants.

Mortality/Morbidity

Death due to dracunculiasis is not caused by the primary infection and occurs only in cases in which secondary infection of the worm's exit site leads to sepsis. The mortality rate is quite low; however, morbidity is a major concern, with secondary infection being the most common complication. Cellulitis or the formation of an abscess requires prompt attention, and pain from the exit sites often can incapacitate patients for weeks. This is usually observed in individuals who have multiple worms and rely on their ability to stand or walk for their livelihood. Farmers with untreated dracunculiasis in Nigeria have been found to miss work for up to 3 months. Infected schoolchildren may miss up to 25% of the school year. Therefore, Dracunculus infection can cause significant socioeconomic burden for individuals and communities.

Another, more chronic, complication of dracunculiasis is encapsulation of the adult worm, which occurs when the calcified remains of the worm persist in the extremity of the patient. This can result in chronic pain and intermittent swelling of the extremity. In a small percentage of individuals who have permanent scarring or deformity of the lower extremity, even after the worm has been extracted, chronic pain may persist for up to 18 months. Notably, on average, infected individuals have multiple worm extrusions at the same time (1.8 worms per person, on average). Rarely, dracunculiasis can present with worms located in anomalous locations, including the lungs, pancreas, testes, spinal cord, or periorbital tissue.

Race

No race predilection exists.

Sex

No sex predilection exists.

Age

Most reported dracunculiasis cases occur in the young adult (working) population who may be exposed to contaminated water sources more frequently; however, no particular age predilection exists.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

• Travel to or residence in endemic countries is invariably part of the history.
• Recollection of ingestion of unfiltered or untreated water, ingestion of fresh fruits or vegetables washed with such water, or bathing or swimming in potentially contaminated water are all possibly elicited in the patient's history. The transmission of the disease has seasonal variation. In arid areas, the rainy season, with increased availability of surface water, coincides with most cases. In wet areas, the dry season, when sources of drinking water are limited, is associated with most cases.
• History tends to be useful only to confirm the diagnosis after it has been presumed based on physical examination findings.

Physical

• A blister forms in the epidermis at a site chosen by the female worm, usually in the lower extremity.
• • Immediately before blister formation, allergic-type symptoms, such as mild respiratory distress with wheezing, urticaria, periorbital edema, and pruritus, are often present.
  • Patients may also be febrile during this period.
  • With the emergence of the worm's head, the blister grows and becomes erythematous at its periphery.
  • Edema occurs around the site, and inflammation of the papule causes further pruritus and burning pain.
  • Usually, after a few days, but possibly as long as 2 weeks, the blister erupts, and the worm releases a collection of larvae-containing fluid.
  • The swelling and pain often are markedly decreased after the blister is opened.
  • At this point, an ulcer forms around the blister site as the adult worm continues to emerge.
• Definitive diagnosis is made when the head of the worm is identified within the ulcer.
• As noted, the ulcer tends to become secondarily infected.
• No other particular physical findings are commonly noted, although some degree of lymphadenopathy may be found at any stage of the illness.

Causes

Dracunculiasis is an infection caused by the nematode D medinensis. The larvae from D medinensis are not infective unless a molting process within the copepods occurs. This requires a fresh-water environment; thus, water ingestion is the only identified mode of transmission.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Onchocerciasis

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• CBC count with differential
• • The WBC count is likely elevated, even if only slightly.
  • The differential commonly indicates eosinophilia.
• Serum immunoglobulin levels
• • Immunoglobulin E (IgE), immunoglobulin G1 (IgG1), and immunoglobulin G4 (IgG4) levels are usually elevated, with variability depending on the stage of disease.
  • Patent infections (immediately following blister eruption but before ulcer formation) cause the greatest elevation of the 2 IgG subclasses, whereas both are relatively less elevated with postpatent (ulcerated) or prepatent (blister in formative stage) infections.

Imaging Studies

• A radiologic examination (plain-film roentgenography) of the lower extremity may prove useful in the identification of calcified worms in the rare case when surgery is considered. Incidental identification of calcified lesions from dracunculiasis has also been reported after radiographic evaluation of a painful lower extremity.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

• The most common practice to treat dracunculiasis still involves wrapping the worm around a stick.
• • The adult worm is extracted from the patient using a stick at the skin surface and wrapping or winding the worm a few centimeters per day.
  • This slow process can take many days and, in some cases, up to a few weeks, but it is required to avoid breakage and leaving behind a portion of the worm.
  • Metronidazole or thiabendazole (in adults) is usually adjunctive to stick therapy and somewhat facilitates the extraction process. However, one study found that antihelminthic therapy was associated with aberrant migration of worms, resulting in infection in areas other than the lower extremity. Therefore, such medications should be used with caution.

Surgical Care

The worm also can be excised surgically where such facilities are available.

Consultations

Suspicion of dracunculiasis based on history or examination findings warrants consultation of an infectious disease specialist for involvement in management and follow-up care. This also allows for initiation of epidemiologic protocol if the patient presents in a nonendemic country.

Diet

No particular dietary changes are required during the extraction process, regardless of the time involved.

Activity

Activity is usually self-restricted because of discomfort. Recommendations are tailored for the individual, with no particular general guidelines.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Drug Category: Antiparasitic agents

These agents are used to speed the pace of worm extraction.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Outpatient Care

• Close follow-up monitoring is necessary to track progression of extraction.
• Initially, warm compresses may be useful in relieving pain.
• Diligent cleaning of the wound site is necessary during and following extraction of the worm.
• Topical antibiotic ointments, such as bacitracin or mupirocin (Bactroban), can be applied to wounds to prevent secondary infection.

Deterrence/Prevention

• Prevention of the disease is through management of water supplies in endemic areas.
• • Treatment of potentially contaminated water with the larvicide temephos (ABATE) is useful in controlling the spread of the infection. Additional preventative steps include filtering water through a finely woven cloth (to strain larvae), drinking water from only a borehole or hand-dug wells, and avoiding passive transmission by educating infected persons to avoid entering water sources.
  • Areas with known outbreaks or more frequent infections must be identified, and equipment must be made available to clear drinking water in those areas.
  • Unfortunately, civil unrest and governmental lapses have prevented clearance of many water supplies in several endemic nations. Numerous positive social and political steps are also important to create conditions for the interruption of disease transmission.

Complications

• See Mortality/Morbidity.

Prognosis

• With treatment, prognosis is very good. Without treatment, prognosis is still very good as long as serious secondary infection does not occur and remain untreated.

Patient Education

• Distribute information regarding the disease in endemic areas.
• Assist communities in maintaining clean drinking water supplies.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Incorrect diagnosis
• • Initially missing the diagnosis of dracunculiasis is possible because of the infrequency of cases throughout the world, particularly in the western hemisphere.
  • Major complications in this scenario include late diagnosis, resulting in an increased degree of individual patient morbidity and failure of timely epidemiologic notification of a case.
  • In suspicious lesions, a travel history must be obtained and remembered to avoid this pitfall.
• Inappropriate treatment
• • Although this scenario is much less likely than the one above, inappropriate treatment of dracunculiasis could be a potential issue, even if the diagnosis is made correctly.
  • Consult an infectious disease specialist in any and all cases of suspected dracunculiasis outside of endemic nations to prevent inappropriate treatment or management.
• Reaction to treatment
• • Care must be taken to ascertain whether the patient with dracunculiasis has ever taken any antiparasitic drugs and if they were ever noted to cause problems.
  • A failure to do so with a resultant adverse reaction to prescribed medication is a clear-cut legal pitfall that should be eliminated in practice by following the standards of care and obtaining an appropriate patient history.

Special Concerns

• Patients with dracunculiasis are at risk for other parasitic infections because areas endemic for Dracunculus also are endemic for other parasites. During and after treatment for dracunculiasis, patients should be monitored for other symptomatology characteristic of parasitic infections.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• Adewale B, Mafe MA, Sulyman MA. Impact of guinea worm disease on agricultural productivity in Owo local government area, Ondo state. West Afr J Med. May-Jun 1997;16(2):75-9. [Medline].
• Behbehani K. Candidate parasitic diseases. Bull World Health Organ. 1998;76 Suppl 2:64-7. [Medline].
• Bimi L, Freeman AR, Eberhard ML, et al. Differentiating Dracunculus medinensis from D. insignis, by the sequence analysis of the 18S rRNA gene. Ann Trop Med Parasitol. Jul 2005;99(5):511-7. [Medline].
• Bloch P, Simonsen PE. Immunoepidemiology of Dracunculus medinensis infections I. Antibody responses in relation to infection status. Am J Trop Med Hyg. Dec 1998;59(6):978-84. [Medline]. [Full Text].
• CDC. Progress toward global eradication of dracunculiasis, January-June 2003. MMWR Morb Mortal Wkly Rep. Sep 19 2003;52(37):881-3. [Medline].
• CDC. Progress toward global eradication of dracunculiasis, January 2004-July 2005. MMWR Morb Mortal Wkly Rep. Oct 28 2005;54(42):1075-7. [Medline].
• Greenaway C. Dracunculiasis (guinea worm disease). CMAJ. Feb 17 2004;170(4):495-500. [Medline]. [Full Text].
• Hopkins DR, Ruiz-Tiben E, Ruebush TK. Dracunculiasis eradication: almost a reality. Am J Trop Med Hyg. Sep 1997;57(3):252-9. [Medline].
• Hopkins DR, Ruiz-Tiben E, Downs P, et al. Dracunculiasis eradication: the final inch. Am J Trop Med Hyg. Oct 2005;73(4):669-75. [Medline].
• Hunter JM. An introduction to guinea worm on the eve of its departure: dracunculiasis transmission, health effects, ecology and control. Soc Sci Med. Nov 1996;43(9):1399-425. [Medline].
• Levinson WE, Jawetz E. Nematodes: Dracunculiasis. In: Medical Microbiology and Immunology. 1994;285-286.
• MMWR Morb Mortal Wkly Rep. Imported dracunculiasis--United States, 1995 and 1997. Mar 27 1998;47(11):209-11. [Medline].
• Menon T. Incidental finding of Dracunculus medinensis in Australia. Med J Aust. Jul 4 2005;183(1):51-2. [Medline].
• Muller R. Guinea worm disease--the final chapter?. Trends Parasitol. Nov 2005;21(11):521-4. [Medline].
• Sam-Abbenyi A, Dama M, Graham S, Obate Z. Dracunculiasis in Cameroon at the threshold of elimination. Int J Epidemiol. Feb 1999;28(1):163-8. [Medline].
• WHO. Dracunculiasis (guinea-worm disease) eradication. Wkly Epidemiol Rec. Apr 16 2004;79(16):154-5. [Medline].

Article Last Updated: Aug 22, 2006