Life cycle of Dracunculus medinensis
, the cause of dracunculiasis (guinea worm disease) in humans
Humans contract dracunculiasis (guinea worm disease) by drinking unfiltered water containing copepods (small crustaceans) which are infected with larvae of the nematode (roundworm) Dracunculus medinensis (1). 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 (2). After maturing iand copulating, the male worms die and the females (length: 70 to 120 cm) migrate in the subcutaneous tissues towards the skin surface (3). Approximately one 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 (4). The larvae are ingested by a copepod (5) and after two weeks (and two molts) have developed into infective larvae (6). Ingestion of the copepods closes the cycle (1).
From Centers for Disease Control Parasites and Health website.