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The diagram shows the transmission cycle as a series of seven numbered stages, beginning, in stage 1, with ingestion of the infected cyclops by drinking contaminated water. In stage 2, guinea worm larvae are released in the stomach and then burrow through the tissues. In stage 3, the worms matures and mates within 3 months in the host’s thorax; then the males die. In stage 4, the females grow for 8–12 months and migrate to the lower limbs where they produce more than 3 million larvae. In stage 5, the larvae are released from the female worm into still water (e.g. a lake) at intervals over a period of 6 weeks as the worm is emerging from the limb to the exterior. In stage 6, cyclops present in the water eat the larvae, which mature inside them, reaching the infective stage in 2 weeks. Finally, in stage 7, drinking water contaminated with the infected cyclops is taken from the lake.

 5.3 The guinea worm transmission cycle