Guinea worm infection (Dracunculiasis)

Infection with D. medinensis results from drinking water infected with the larvae which have been ingested by a minute crustacean (cyclops) or water fleas. It is therefore most common in rural areas and where there is poor sanitation. The worm burrows into the deep connective tissues after fertilization. The female guinea worm migrates to areas most likely to come into contact with water, such as the lower leg and the lower part of the body, and the larvae then develop. This may take more than a year. The female worm may reach 30 cm or more in length (the smaller male worm probably dies after copulation). Clinically, a blister or ulcer develop on the skin, showing where the guinea worm will shead its larvae into the water to complete the cycle. Just prior to release, the patient may be quite ill, with vomiting, diarrhoea, pruritus and giddiness. Later, after sheading the larvae, the guinea worm dies and the resulting foreign body and granulation tissue may calcify. Radiologically, this results in a long string-like calcification, which may be coiled or remain stretched along the leg, across the tissues of the abdomen or the chest, or deeper within the peritoneum (Fig. 42). Guinea worms, alive or dead, can be localised by ultrasound and are easily seen on plain radiography when calcified. Arthritis may occur if the worm is near a joint, or abscesses may

a	Figure 42. Guinea worm. a) A curled, partially calcified guinea worm within a soft tissue abscess of the lower leg. (Nigeria) b) Several long, and other curled calcified guinea worms in the thigh and scrotum. (Nigeria)
b

Philip E.S. Palmer, with Stanley P. Bohrer, Carlos Bruguera, Xing-Rong Chen, Mahmoud R. EImeligi, Hassen A. Gharbi, S.B. Lagundoye, M. W. Wachira