Just saw this story that the WHO announced this week that it could eradicate guinea worm from the globe in two years. Pretty incredible feat, eliminating disease altogether. And this one in particular will be nice to see disappear: More specifically known as dracunculiasis, guinea worm infections are particularly nasty. Here's how it works: Worm larvae live in water, and wait for a host-human to drink - then the larvae make their way from the intestines towards the lower extremities (usually the feet). In a nefarious bit of evolution, the worm festers just below the skin, causing a blister which is characterized by a burning sensation. The burning causes the host to, often enough, soak their foot in water - which is just what the worm has been waiting for. Once in contact with water, the worm releases thousands of larvae and the cycle starts all over again. The treatment is usually to draw the worm out of the body by twisting it around a stick - a grusome method that's been practiced for centuries and may be the source for the symbol of medicine, shown above, the Caduceus (though there's some debate about this).
The Gates Foundation has helped the WHO attack guinea worm, and this accomplishment nicely vindicates their stated mission of eradicating - not just containing or alleviating - the worst infectious diseases on earth. I should note that it's not clear to me whether they are actually on the way to eradicating the very worm itself - ie, elimate the species from the face of the earth, which is kinda remarkable (didn't even need DDT!) - or simply make it so rare as to be effectively eliminated from endemic areas. Either way, it's an amazing achievement - and is likely to give much encouragement to the folks at Gates and elsewhere that disease is, indeed, something we can target and eliminate, given the resources, ambition, and sustained effort. That was certainly the conviction of Pasteur and Koch back in the late 19th century, as I wrote recently. But it hasn't been a realistic target, many would say, for decades now.
As it happens, I had an interesting conversation a few days ago with D.A. Henderson, who ran the WHO's project to eliminate smallpox in the 60s and 70s, and is widely credited with eliminating that scourge from the face of the earth. I asked him what he made of the ambition of Gates and others to eliminate, rather than contain, disease. You might think that, given his own success, Henderson would be one to encourage others to pursue the path of eradication. In fact, he said entirely the opposite: smallpox was the exception, he said, and making 'eradication' your benchmark is a dangerously high goal. He shared a funny story about the idea: "In 1980 I was invited to speak at a meeting to identify what to go after for eradication after smallpox," he said. His answer: Given the technology and resources available, he said, he saw no realistic targets on the horizon. "They never invited me to another one of those meetings," he said with a smile.