Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android

37-25: Dracunculiasis

Philip J. Rosenthal

ESSENTIALS OF DIAGNOSIS

ESSENTIALS OF DIAGNOSIS

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

GENERAL CONSIDERATIONS

Dracunculiasis is caused by the nematode Dracunculus medinensis, or Guinea worm. It causes chronic cutaneous ulcers with protruding worms in rural Africa. It was a major cause of disability, but recent control efforts have been remarkably successful. Annual incidence has decreased from about 3.5 million cases in the late 1980s to 15 reported cases in 2021; recent cases were from Chad, Ethiopia, South Sudan, Mali, and Angola. Remarkably, the first case ever described in Angola was reported in 2018. Of concern, infection has also been identified in domestic dogs and cats in endemic countries, with dogs likely providing an important disease reservoir, and reported animal cases now outnumber human cases.

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 (eFigure 37–40). A subcutaneous ulcer then forms (eFigure 37–41). 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. Worm death and disintegration in tissue may provoke a severe inflammatory reaction.

eFigure 37–40.

Worm blister caused by the head of a female Guinea worm (Dracunculus medinensis). A: The female Guinea worm induces a painful blister. B: After rupture of the blister, the worm emerges as a whitish filament in the center of a painful ulcer, which is often secondarily infected. (Reproduced with permission from Global 2000/The Carter Center, Atlanta, Georgia.)

2 photos of a worm blister. Photo A depicts a blister on the foot. Photo B shows the Guinea worm emerging as a whitish filament in the center of the ulcer.
View Full Size||Download Slide (.ppt)
2 photos of a worm blister. Photo A depicts a blister on the foot. Photo B shows the Guinea worm emerging as a whitish filament in the center of the ulcer.
View Full Size||Download Slide (.ppt)
eFigure 37–41.

Life cycle of Dracunculus medinensis (Guinea worm). Humans become infected by drinking unfiltered water containing copepods (small crustaceans) that are infected with larvae of D medinensis

image. Following ingestion, the copepods die and release the larvae, which penetrate the host stomach and intestinal wall and enter the abdominal cavity and retroperitoneal space
image. After maturation into adults and copulation, the male worms die and the females (length: 70–120 cm) migrate in the subcutaneous tissues toward the skin surface
image. Approximately 1 year after infection, the female worm induces a blister on the skin, generally on the distal lower extremity, which ruptures. When this lesion comes into contact with water, a contact that the patient seeks to relieve the local discomfort, the female worm emerges and releases larvae
image. The larvae are ingested by a copepod
image and after 2 weeks (and two molts) have developed into ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.

This site uses cookies to provide, maintain and improve your experience. MH Privacy Center Close