eMedicine Specialties > Pediatrics: General Medicine > Parasitology

Dracunculiasis

Shuvo Ghosh, MD, Developmental-Behavioural Pediatrician, Assistant Professor of Pediatrics,Child Development Program, Division of General Pediatrics, McGill University Health Centre/Montréal Children's Hospital
Raoul Wientzen, MD, Chief, Professor, Department of Pediatrics, Division of Pediatric Infectious Disease, Georgetown University School of Medicine

Updated: Aug 22, 2006

Introduction

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

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

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.

Differential Diagnoses

Filariasis

Other Problems to Be Considered

Onchocerciasis

Workup

Laboratory 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

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

Antiparasitic agents

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

Metronidazole (Flagyl, Protostat)

DOC as therapy adjunctive to extraction. Active against various anaerobic bacteria and protozoa. Intermediate-metabolized compounds formed bind DNA and inhibit protein synthesis, causing cell death.

Dosing

Adult

250 mg PO tid for 10 d

Pediatric

25 mg/kg/d PO divided tid for 10 d; not to exceed 750 mg/d

Interactions

Cimetidine may increase toxicity of metronidazole; may increase effects of anticoagulants; may increase toxicity of lithium and phenytoin; disulfiramlike reaction may occur with orally ingested ethanol

Contraindications

Documented hypersensitivity; first trimester of pregnancy

Precautions

Pregnancy

B - Usually safe but benefits must outweigh the risks.

Precautions

Do not use during first trimester of pregnancy; use caution with history of hepatic disease or concurrent hepatotoxic drugs; use cautiously with coagulopathies, history of retinal or visual changes, or CNS dysfunction

Thiabendazole (Mintezol)

Acceptable for use in adults only.
Inhibits helminth-specific mitochondrial fumarate reductase; alleviates symptoms of trichinosis during invasive phase.

Dosing

Adult

50-75 mg/kg/d PO divided bid for 3 d; not to exceed 3 g/d

Pediatric

Not recommended

Interactions

May elevate serum levels of theophylline, increasing toxicity (monitor serum levels and reduce dose prn)

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

C - Safety for use during pregnancy has not been established.

Precautions

Closely monitor in hepatic or renal dysfunction; before initiating therapy, supportive therapy is necessary for anemic, dehydrated, or malnourished patients; use in confirmed worm infestation (not prophylactically); may cause nausea, vomiting, and mild CNS depression

Follow-up

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

Medicolegal 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

1. 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].

2. Behbehani K. Candidate parasitic diseases. Bull World Health Organ. 1998;76 Suppl 2:64-7. [Medline].

3. 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].

4. 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].

5. CDC. Progress toward global eradication of dracunculiasis, January-June 2003. MMWR Morb Mortal Wkly Rep. Sep 19 2003;52(37):881-3. [Medline].

6. CDC. Progress toward global eradication of dracunculiasis, January 2004-July 2005. MMWR Morb Mortal Wkly Rep. Oct 28 2005;54(42):1075-7. [Medline].

7. Greenaway C. Dracunculiasis (guinea worm disease). CMAJ. Feb 17 2004;170(4):495-500. [Medline]. [Full Text].

8. Hopkins DR, Ruiz-Tiben E, Ruebush TK. Dracunculiasis eradication: almost a reality. Am J Trop Med Hyg. Sep 1997;57(3):252-9. [Medline].

9. 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].

10. 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].

11. Levinson WE, Jawetz E. Nematodes: Dracunculiasis. In: Medical Microbiology and Immunology. 1994;285-286.

12. MMWR Morb Mortal Wkly Rep. Imported dracunculiasis--United States, 1995 and 1997. Mar 27 1998;47(11):209-11. [Medline].

13. Menon T. Incidental finding of Dracunculus medinensis in Australia. Med J Aust. Jul 4 2005;183(1):51-2. [Medline].

14. Muller R. Guinea worm disease--the final chapter?. Trends Parasitol. Nov 2005;21(11):521-4. [Medline].

15. 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].

16. WHO. Dracunculiasis (guinea-worm disease) eradication. Wkly Epidemiol Rec. Apr 16 2004;79(16):154-5. [Medline].

Keywords

dracunculiasis, dracontiasis, dracunculosis, guinea worm infection, Dracunculus medinensis, D medinensis, guinea fire worm, Medina worm, serpent worm, dragon worm

Contributor Information and Disclosures

Author

Shuvo Ghosh, MD, Developmental-Behavioural Pediatrician, Assistant Professor of Pediatrics,Child Development Program, Division of General Pediatrics, McGill University Health Centre/Montréal Children's Hospital
Shuvo Ghosh, MD is a member of the following medical societies: American Academy of Pediatrics and Physicians for Social Responsibility
Disclosure: Nothing to disclose.

Coauthor(s)

Raoul Wientzen, MD, Chief, Professor, Department of Pediatrics, Division of Pediatric Infectious Disease, Georgetown University School of Medicine
Raoul Wientzen, MD is a member of the following medical societies: American Academy of Pediatrics and Phi Beta Kappa
Disclosure: Nothing to disclose.

Medical Editor

Michael D Nissen, MBBS, BMedSc, FRACP, FRCPA, Associate Professor in Biomolecular, Biomedical Science & Health, Griffith University; Director of Infectious Diseases and Unit Head of Queensland Paediatric Infectious Laboratory, Sir Albert Sakzewski Viral Research Centre, Royal Children's Hospital
Michael D Nissen, MBBS, BMedSc, FRACP, FRCPA is a member of the following medical societies: American Academy of Pediatrics, American Society for Microbiology, Pediatric Infectious Diseases Society, Royal Australasian College of Physicians, and Royal College of Pathologists of Australasia
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc
Disclosure: Pfizer Inc Stock Investment from broker recommendation; Avanir Pharma Stock Investment from broker recommendation

Managing Editor

Martin Weisse, MD, Program Director, Associate Professor, Department of Pediatrics, West Virginia University
Martin Weisse, MD is a member of the following medical societies: Ambulatory Pediatric Association, American Academy of Pediatrics, and Pediatric Infectious Diseases Society
Disclosure: Nothing to disclose.

CME Editor

Robert W Tolan Jr, MD, Chief of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine
Robert W Tolan Jr, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa, and Physicians for Social Responsibility
Disclosure: GlaxoSmithKline Honoraria Speaking and teaching; MedImmune Honoraria Consulting; MedImmune Honoraria Speaking and teaching; Merck Honoraria Speaking and teaching; Novartis Honoraria Speaking and teaching; sanofi pasteur Grant/research funds Unrestricted research grant; sanofi pasteur  Consulting; sanofi pasteur Honoraria Speaking and teaching; Tap Honoraria Speaking and teaching

Chief Editor

Russell W Steele, MD, Professor and Vice Chairman, Department of Pediatrics, Head, Division of Infectious Diseases, Louisiana State University Health Sciences Center
Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, and Southern Medical Association
Disclosure: None None None

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