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For further information, see CMDT Part 35-25: Dracunculiasis

Key Features

Essentials of Diagnosis

  • Tender cutaneous ulcer and worm protruding from the skin of an individual who has ingested untreated water in rural Africa

  • Worm death and disintegration in tissue can provoke a severe inflammatory reaction

General Considerations

  • Caused by the nematode Dracunculus medinensis, or Guinea worm

  • Infection occurs after swallowing water containing the infected intermediate host, the crustacean Cyclops (known as copepods or water fleas)

  • In the stomach, larvae escape from the copepods and migrate through the intestinal mucosa to the retroperitoneum, where mating occurs

  • Females then migrate to subcutaneous tissue, usually of the legs, over about a year

  • A subcutaneous ulcer then forms

  • Upon contact with water, the parasite discharges large numbers of larvae, which are ingested by copepods

  • Adult worms, which can be up to a meter in length, are gradually extruded


  • Was a major cause of disability; control efforts have been remarkably successful

  • Annual incidence has decreased from about 3.5 million cases in the late 1980s to 27 reported cases in 2020

  • All cases were from Chad, Ethiopia, South Sudan, Mali, and Angola

  • Has been identified in domestic dogs and cats in endemic countries, with dogs likely an important disease reservoir; reported animal cases now outnumber human

Clinical Findings

Symptoms and Signs

  • Patients are usually asymptomatic until the time of worm extrusion when a painful papule develops, with erythema, pruritus, and burning

  • Multiple lesions may be present

  • A short-lived systemic reaction may develop in some patients and may include

    • Fever

    • Urticaria

    • Nausea, vomiting, diarrhea

    • Dyspnea

  • The skin lesion vesiculates over a few days, followed by ulceration

  • The ulcer is tender, often with a visible worm

  • The worm is then extruded or absorbed over a few weeks, followed by ulcer healing

  • Secondary infections, including infectious arthritis and tetanus, are common

  • Resultant deformities are common with ankle and knee joint infections

  • Lesions commonly prevent walking for a month or more

Differential Diagnosis

  • Cutaneous larva migrans

  • Loiasis (Loa loa infection)

  • Rat bite fever

  • Gnathostomiasis

  • Myiasis

  • Other causes of leg ulcer

    • Venous or arterial insufficiency

    • Bacterial pyoderma

    • Vasculitis

    • Pyoderma gangrenosum


  • Diagnosis follows identification of a typical skin ulcer with a protruding worm

  • When worm is not visible, larvae may be identified on smears or seen after immersion in cold water



  • No drug cures the infection

  • However, metronidazole and mebendazole are sometimes used to limit inflammation and facilitate worm removal

  • Corticosteroid ointments may hasten healing

  • Topical antibiotics may limit bacterial superinfection


  • When available, ...

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