Guinea Worm Disease: Eradication Foreseen
Posted: Wednesday, October 05, 2011
by Jack H. Schick
I read somewhere that there are more worms, on the planet than any other non-microscopic beast. Of course, we're told that "what awaits Man is worms." I don't think they're talking about night crawler earth worms. I think they're talking about the nematodes, the round worms. Nematodes are everywhere, waiting for us. Half the time they don't even wait until we're dead to start eating us. I get the creeps just thinking about the trillions of tiny, string like, crawly round worms infesting every niche in the ecosystem, patiently waiting to get at us, or more likely, to get inside of us to start eating, defecating and laying eggs.
The Guinea worm is one of the best documented human parasites. Dracunculiasis, infestation by guinea worms, has been recognized as a disease for thousands of years. Mention of it first appears in the Egyptian medical document, the Ebers Papyrus, from 1550BC. Evidence of the affliction has been found in calcified Egyptian mummies. It is believed that Guinea worms were being described in the bible (Numbers 21 4-9), when "…the Lord sent fiery serpents among the people, and they bit the people; and much people of Israel died."
In the 2ndcentury BC, Greek writer Agatharchides said the aliment was endemic among nomads in what is now Sudan and along the Red Sea coast. The traditional (and still used today), method of extracting the Guinea worm from a human is to twist it around a stick and pull it out of the open wound it causes. The rod of Asclepius, (a rod with a snake like creature coiled around it) has been a symbol of medicine since ancient Greek times. It is thought to have been derived from the treatment.
Dracunculiasis is Latin and means "affliction with little dragons." A high incidence of the infestation in the Arabian city of Medina led to it being included as part of the scientific name for the parasite, "medinensis." When they began world colonization, Europeans also encountered a large incidence of the ailment along the Guinea coast of West Africa in the 1600's, and gave it its, now most common name, Guinea worm disease.
Guinea worm disease is caused by drinking water that is contaminated with water fleas that, in turn, contain Dracunculus larvae. If the contaminated water is consumed by people without filtering out the fleas ‘catching' the disease is inevitable. The flea is digested by stomach acids, but the larvae survive. They disperse into the body cavity and mate. The male dies and is absorbed, but the female burrows deeper into connective tissues, next to long bones or into joints of the lower extremities to mature. The process takes about three months after the initial infection. As the worm grows, it moves through the subcutaneous tissue and causes a burning sensation, hence the fiery dragon.
After about a year, the worm creates a blister in the host's skin--usually in the leg or foot. Within 72 hours the blister ruptures, exposing the posterior end of the worm. The broken blisters cause a very intense burning sensation as the worm emerges. The victims often immerse the affected limb in water to ease the pain. When in contact with water the Guinea worm releases hundreds of thousands of larvae, contaminating the water source. They are eaten by water fleas, which are consumed by people drinking the unfiltered or unpurified water and the cycle continues. Infection does not create immunity. A person can be afflicted with Guinea worm disease repeatedly.
There is no vaccine or medicine to treat Guinea worm disease. There is only one remedy. Once it begins to emerge a person must wrap the live worm around a piece of gauze or a stick and pull it from the body. It is a long, painful process which usually takes weeks or months. The female Guinea worm can reach lengths of two to three feet and be as thick as a spaghetti noodle. Guinea worm disease is not usually fatal. The wounds where the worm emerges can develop infections, however. Antibiotic ointments and analgesics are used on the site. Metronidazole and thiabendazole are often used to make extraction easier, but they can also cause the worm to migrate to a different area of the body.
Guinea worm disease can have a serious economic impact. Worm emergence usually occurs during planting or harvesting seasons. The pain associated with the process prevents many people from working or attending school for as long as three months. Due to a reduced labor force, food shortages and decreased earnings are sometimes experienced. One study found that, in southeastern Nigeria alone, rice farmers lost up to $20 million in one year due to outbreaks of Guinea worm disease.
A global campaign to eliminate Guinea worm disease began in 1980. In 1986, there were an estimated 3.5 million cases of the disease in twenty nations of Asia and Africa. Due to eradication efforts, by 2009, incidences were reduced by 99% to 3,190. All but five of those were in the four countries where the disease is still endemic: Sudan, Ghana, Mali and Ethiopia. In 2010 the number of cases was reduced even further to a total reported of 1,797. Ghana had the best success by reducing from 242 to only eight cases between 2009 and 2010.
Guinea worm disease can only be transmitted by drinking contaminated water. Simple measures to prevent it include:
Drink only from underground water sources free from contamination.
Filter drinking water to remove the water fleas.
Prevent people with emerging Guinea worm from entering water sources.
Repair or develop new drinking water sources that lack the parasites.
Use larvicides to kill worm carrying organisms.
The World Health Organization is the international body that monitors world diseases and is the only one who can declare a disease eradicated. In conjunction with them and the U.S. Center for Disease Control and Prevention, the (Jimmy) Carter Center has made great efforts toward the elimination of this horrifying human affliction. It is estimated that success can be achieved by 2015. If so, Dracunculiasis will be the first parasitic disease to be eradicated and the first disease to be eliminated without the use of vaccines or medical treatment.
Former President Carter was in London this week to appeal for donors to join Britain in the campaign to wipe out the crippling, painful affliction. British officials have pledged $31 over four years to help with the effort--but only if the Carter Center can get matching funds.
I might pitch in a few bucks for that. The idea of sitting by the old watering hole, pulling a three foot long, wiggling strand of spaghetti out of a sore on my leg by twirling it around a stick makes me squirm. The idea that there are at least 16,000 more species of parasitic nematodes waiting for a chance to burrow into my hide or crawl in through one of my orifices scares me. I know they're out there, everywhere, just awaitin', and they are gonna get me someday. I just hope they wait until I quit breathing.
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