Guinea worm fell from 3.5 million cases to 10, with no drug or vaccine
In 1986 an estimated 3.5 million people across 20 countries caught Guinea-worm disease. In 2025, just 10 human cases were reported worldwide. No vaccine or cure exists, so the collapse came from filtering water, treating ponds and teaching people how the parasite spreads. It could become only the second human disease ever eradicated.
The culprit is a roundworm, Dracunculus medinensis, whose larvae live inside copepods, tiny crustaceans in stagnant water. Swallow the water and stomach acid dissolves the copepod, freeing larvae that bore through the gut wall. About a year later a mature female travels to the skin, usually of the lower leg or foot, and raises a burning blister. When the sufferer cools the wound in water, the worm releases a flood of larvae, restarting the cycle.
No medicine kills the worm. Treatment is patient and mechanical: the emerging worm is wound around a small stick, a few centimetres a day, over days to weeks, because pulling too hard can snap it inside the wound. People are laid up for the three to ten weeks it takes, and about half suffer substantial disability. Infection gives no immunity, and in farming villages outbreaks at planting or harvest time earned it the name empty granary disease.
Physicians of Greco-Roman antiquity described something matching it, and across the 1800s and into the early 1900s it struck up to 48 million people a year across Africa and South Asia. Eradication work began in the 1980s, after smallpox was wiped out in 1977. Cases dropped below 100,000 in 1997, below 1,000 in 2012 and below 100 in 2015, and 16 formerly endemic countries have since ended transmission.
The disease now lingers mainly in Chad, Ethiopia and South Sudan, and the World Health Organization set 2027 as its eradication target. The final stretch is hard: dogs also carry the parasite, and conflict, weak health systems and funding gaps threaten surveillance just as attention may fade. The tools remain simple, including nylon or cloth filters, filter straws, the larvicide temephos, deep wells, and campaigns urging people not to soak wounds in sources used for drinking.
Source: Dracunculiasis
