Dracunculiasis

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

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

Demographics

• 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 126 reported cases in 2014, 22 reported cases in 2015, 25 in 2016, 30 in 2017 all from South Sudan, Mali, Chad, and Ethiopia; 1 case in 2018 in Angola

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

Medications

• 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

Surgery

• When available, simple surgical procedures can be used to remove worms

Therapeutic Procedures

• Wet compresses may relieve discomfort

• Occlusive dressings improve hygiene and limit shedding of infectious larvae

• Worms are typically removed by sequentially rolling them out over a small stick

Prevention

• Avoid contaminated drinking water by

  • Boiling

  • Chlorinating

  • Filtering through finely woven cloth

• A WHO eradication program, initiated in 1986, has been highly successful

When to Refer

• For manual or surgical extraction