Life Cycle/ Geographic Distribution--Dracunculus mediensis
  • Life Cycle:
    • "Humans become infected by drinking unfiltered water containing copepods (small crustaceans) which are infected with larvae of D. medinensis.
      • Following ingestion, the copepods are killed and release the larvae, which penetrate the host stomach and intestinal wall and enter the abdominal cavity and retroperitoneal space.
      • After maturation into adults and copulation, the male worms die and the females (length: 70 cm to 120 cm) migrate in the subcutaneous tissues towards the skin surface.
      • 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 into the water.
      • The larvae are ingested by a copepod and after two weeks (and two molts) have developed into infective larvae. Ingestion of the copepods closes the cycle."
  • Geographic Distribution:
    • "An ongoing eradication campaign has dramatically reduced the incidence of dracunculiasis, which is now restricted to rural, isolated areas in a narrow belt of African countries and Yemen."
  • courtesy of the Division of Parasitic Diseases at the National Center for Infectious Diseases, Centers for Disease Control & Prevention
  • http://www.dpd.cdc.gov/DPDx/HTML/Dracunculiasis.htm