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A parasite that has been eating people for 3,500 years is about to be wiped off the planet. It infected 3.5 million people in 1986. Last year, it infected 10. And I have not seen it make a single front page. It is called Guinea worm. You drink contaminated water from a pond in a poor village. A year later, a worm up to three feet long starts coming out of your leg through a burning blister. There is no pill that stops it and no surgery that works. You wrap the worm around a stick and pull it out slowly, over days or weeks, inch by inch. If you rush, the worm breaks inside you and causes a fresh infection. Guinea worm is ancient. Preserved worms have been pulled out of Egyptian mummies from around 1000 BCE. The Ebers Papyrus, an Egyptian medical scroll from 1550 BCE, describes pulling the worm out with a stick. For three and a half thousand years, that was the best humans could do. Then in 1986, public health workers decided to kill the parasite off. They had no vaccine and no drug. What they had was cheap cloth water filters and a small army of volunteers willing to walk from village to village for decades. The plan was simple. Give everyone who drinks from a pond a cloth filter to strain out the tiny water fleas that spread the parasite. Then send volunteers walking house to house, year after year, teaching people how to use the filters and keeping anyone with an emerging worm out of the water. It worked. From 3.5 million cases a year to 10. Four were in Chad, four in Ethiopia, two in South Sudan. The other four countries where the worm used to be common, Angola, Cameroon, the Central African Republic, and Mali, had zero human cases for the second year in a row. The World Health Organization has already certified 200 countries as Guinea worm free. Six are left. The last hurdle is dogs. Cameroon had 445 infected animals last year and Chad had 147, so a lot of the remaining work is on animals, not humans. Strays get leashed, and crews treat ponds to kill any remaining worms. The campaign keeps watching until the number hits zero. When Guinea worm hits zero, it becomes the second human disease ever erased from the planet. The first was smallpox. It will also be the first parasite humans have ever wiped out, and the first disease ever ended without a single dose of medicine. Volunteers walked village to village with cloth filters for 40 years. Now a plague from the age of the pharaohs is about to be gone.