In one of the most charming bits of writing I've come across of late, Carl Zimmer offers up a "fond obituary" for the guinea worm. It's one of 17 neglected tropical diseases (NTD to us nerds) getting renewed attention -- and, in the guinea worm's case, a likely end date -- from World Health Organization.
That's good news from a public health standpoint, of course. Guinea worm infections sound painful and nasty. Even Zimmer says he "will not miss it as a disease" -- and yet -- "as an animal, it will leave a mind-boggling absence."
Howso? Zimmer explains:
"The guinea worms have wound themselves around human history for thousands of years. Egyptian mummies contained them. The Book of Numbers describes how the Israelites were stricken by “fiery serpents” as they wandered the desert–they, too, are believed to be guinea worms. Muslim pilgrims on the hajj suffered from guinea worm infections on their way to Medina, which led to its Latin name, which means “Little Dragon of Medina.” Greek and Persian doctors were winding the worms on sticks over two thousand years ago. It’s possible that the symbol of medicine–snakes coiled around a staff–maybe actually represent this ancient treatment."
In case that makes you nostalgic:
"Of all the many remarkable things about the guinea worm, here is something particularly remarkable: this journey causes its victim no pain. It’s not a fleeting infection, either. It takes the guinea worms three to four months to become sexually mature. The males only get to be 4 centimeters long; the females reach 25 times that length. Most of that extra space in their bodies is taken up by their uterus. If people have both males and females in their body, they can find each other and mate. After this internal congress, the male guinea worm creeps off to some corner of the body and dies. The female, meanwhile, swells with progeny. Three million embryos begin to grow inside her.
It takes months for the multitudes she contains to grow to the point when they’re ready to leave their mother–and their human world. She begins her journey to ground, slithering through the connective tissue until she reaches her host’s leg and creeping down further towards the foot. Only now, over a year after taking in the guinea worms, does a person become aware of what’s been happening. The guinea worm mother pierces the skin from the inside and releases an irritant that creates a painful blister–”burning without cease” as one tropical disease expert once put it.
There is only one balm for this pain: water. When people splash water on the blister, the guinea worm responds by twisting into a contraction and vomiting embryos from her mouth."
Don't even think about yanking the thing out: The worm retracts and dies. The leg swells, and the dead worm becomes "a site of infection," which can kill the human host.
So what's the loss, then? There's no treatment for guinea worm infections, Zimmer explains, save the extraction of the thing. So eradicating guinea worm infections means eradicating guinea worm. It means eliminating a whole species -- one about which we don't actually know that much. Zimmer enumerates the lost knowledge:
"No one has sequenced the guinea worm genome. No one has used new staining technology to make its neurons light up. We don’t know how long it has infected humans, or where it came from before that. What little we do know should make us intensely curious about what we don’t know–and what we may never know."
Read the whole piece. It is by turns thought-provoking, terrifying and delightful.