Guinea worm disease is transmitted to humans through drinking contaminated water which contain Cyclops which host D. medinensis larvae. Immersion of the papule or ulcer in water can also trigger release of larvae from the worm into the water source, which then are uptaken by the Cyclops water flea.

There is no evidence that an animal reservoir exists for the Guinea worm, which makes it an easier disease to eradicate. However, domestic animals and mammals can be infected as accidental hosts.



The Cyclops crustacean or water flea is the only vector or intermediate host. Its size is 1-2 mm and after it ingests the larvae, it develops to the stage at which it can infect humans 14 days thereafter.