lpetrich
Contributor
Carter Center Guinea Worm Eradication Program The guinea worm, Dracunculus medinensis, is a nematode with a life cycle that is very nasty to us, causing (of course) dracunculiasis or guinea worm disease. Its common name comes from Guinea in West Africa, and its Linnaean name was invented by Carolus Linnaeus himself, meaning the "little dragon from Medina".
Guinea worms have been known for millennia in parts of Africa and Asia, and we and our ancestors may well have suffered from them for at least the last few million years. They are mentioned in the Ebers Papyrus, an Egyptian medical treatise written around 1550 BCE. That document mentions the only known treatment, even after over 3500 years: slowly pull the worm out by winding it around a stick. Very slowly; it can take as long as a month. No cure or vaccine for it is known.
There is a likely reference to them in the Bible: Numbers 21:5 "The Lord sent fiery serpents among the people and they bit the people, so that many people of Israel died."
That treatment may also have inspired the Rod of Asclepus, a snake coiled around a staff. The caduceus of Hermes is a pair of snakes coiled around a staff.
Guinea worms come in two separate sexes, with the female ones growing as much as 800 mm long and the male ones as much as 40 mm long. This is *very* long by nematode standards; most nematodes grow only a few mm long. However, the worms are about 1 - 2 mm wide.
In its larval stage, it infects copepods, like water fleas.
It passes on to its human host by that person drinking water containing infected copepods. As they are digested away, the worms wiggle through the gut and into the abdominal cavity. After three months, the worms mate and the male ones then die. About a year later, the surviving worms, all female, move to the lower legs, and they stick their tail ends through the skin, often at the hosts' feet. It makes a painful, burning sensation, and the worms' hosts often try to alleviate that pain by putting their legs and feet in some water. The worms then release some larvae, and the larval worms then look for some copepods to infect, completing the cycle.
The exit spot can get infected, adding to the pain, and this disease is painful enough to interfere with schooling and work for some months.
Though the guinea worm's preferred large host is our species, its close relatives prefer different species.
Back in 1986, the guinea worm produced an estimated 3.5 million new infections per year in 17 African countries, and also Yemen, Pakistan, and India. But eradication efforts by the Carter Center and other organizations have reduced this number drastically. They have concentrated on prevention, like filtering and boiling drinking water, and keeping infected people away from drinking-water supplies. As as result, there were only 126 reported infections in 2013. Also, the worm has not appeared from any area that it has been eradicated from.
This suggests that the guinea worm is being driven into extinction, and that it will soon suffer the fate of the smallpox virus. That virus nowadays exists only in labs, though its genome has been sequenced. Likewise, the polio virus is almost eradicated, and it now exists in the wild only in a few African and Asian countries. However, civil wars and Islamist conspiracy mongers have interfered with that last bit of eradication.
It would be a good idea to get the guinea worm's genome before that worm joins the smallpox virus. But some gene sequencers are working on it: Helminth Genomes Initiative - Wellcome Trust Sanger Institute, Dracunculus medinensis - NematodeGenomes
Some other human-disease organisms are similarly vulnerable, because they need a human host in their lifecycle, notably the AIDS virus and the syphilis and gonorrhea bacteria. These organisms are often transmitted by sexual contact, something that has made many people unwilling to address them in an appropriate fashion -- many people seem to think that sexually transmitted diseases are punishments for the sins of their sufferers.
Dracunculiasis, Dracunculus medinensis, Ebers Papyrus, Smallpox, Polio
Guinea worms have been known for millennia in parts of Africa and Asia, and we and our ancestors may well have suffered from them for at least the last few million years. They are mentioned in the Ebers Papyrus, an Egyptian medical treatise written around 1550 BCE. That document mentions the only known treatment, even after over 3500 years: slowly pull the worm out by winding it around a stick. Very slowly; it can take as long as a month. No cure or vaccine for it is known.
There is a likely reference to them in the Bible: Numbers 21:5 "The Lord sent fiery serpents among the people and they bit the people, so that many people of Israel died."
That treatment may also have inspired the Rod of Asclepus, a snake coiled around a staff. The caduceus of Hermes is a pair of snakes coiled around a staff.
Guinea worms come in two separate sexes, with the female ones growing as much as 800 mm long and the male ones as much as 40 mm long. This is *very* long by nematode standards; most nematodes grow only a few mm long. However, the worms are about 1 - 2 mm wide.
In its larval stage, it infects copepods, like water fleas.
It passes on to its human host by that person drinking water containing infected copepods. As they are digested away, the worms wiggle through the gut and into the abdominal cavity. After three months, the worms mate and the male ones then die. About a year later, the surviving worms, all female, move to the lower legs, and they stick their tail ends through the skin, often at the hosts' feet. It makes a painful, burning sensation, and the worms' hosts often try to alleviate that pain by putting their legs and feet in some water. The worms then release some larvae, and the larval worms then look for some copepods to infect, completing the cycle.
The exit spot can get infected, adding to the pain, and this disease is painful enough to interfere with schooling and work for some months.
Though the guinea worm's preferred large host is our species, its close relatives prefer different species.
Back in 1986, the guinea worm produced an estimated 3.5 million new infections per year in 17 African countries, and also Yemen, Pakistan, and India. But eradication efforts by the Carter Center and other organizations have reduced this number drastically. They have concentrated on prevention, like filtering and boiling drinking water, and keeping infected people away from drinking-water supplies. As as result, there were only 126 reported infections in 2013. Also, the worm has not appeared from any area that it has been eradicated from.
This suggests that the guinea worm is being driven into extinction, and that it will soon suffer the fate of the smallpox virus. That virus nowadays exists only in labs, though its genome has been sequenced. Likewise, the polio virus is almost eradicated, and it now exists in the wild only in a few African and Asian countries. However, civil wars and Islamist conspiracy mongers have interfered with that last bit of eradication.
It would be a good idea to get the guinea worm's genome before that worm joins the smallpox virus. But some gene sequencers are working on it: Helminth Genomes Initiative - Wellcome Trust Sanger Institute, Dracunculus medinensis - NematodeGenomes
Some other human-disease organisms are similarly vulnerable, because they need a human host in their lifecycle, notably the AIDS virus and the syphilis and gonorrhea bacteria. These organisms are often transmitted by sexual contact, something that has made many people unwilling to address them in an appropriate fashion -- many people seem to think that sexually transmitted diseases are punishments for the sins of their sufferers.
Dracunculiasis, Dracunculus medinensis, Ebers Papyrus, Smallpox, Polio