Malaria is still a long way from eradication (see previous article). But dracunculiasis is almost gone. According to a report published on January 16th by the Carter Centre, an American charity, only 148 people now harbour Guinea worm, which causes it. Guinea worms are nematodes that grow under the skins of their human hosts, to a length (if female) of half a metre or more, before emerging over the course of several days in a filament from which pieces break off and shed larvae. These larvae, if they reach water, are then consumed by tiny crustaceans called copepods. If an infested copepod is drunk by someone who has not filtered his water properly, the larvae migrate to his skin and the cycle starts again.
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