Dracunculiasis, more commonly known as Guinea worm disease (GWD) or Medina Worm, is a parasitic infection caused by the nematode, Dracunculus medinensis. The name, dracunculiasis, is derived from the Latin "affliction with little dragons".The common name "Guinea worm" appeared after Europeans first saw the disease on the Guinea coast of West Africa in the 17th century.The painful, burning sensation experienced by the infected patient has led to the disease being called "the fiery serpent".
As the worm moves downwards, usually to the lower leg, through the subcutaneous tissues, it leads to intense pain localized to its path of travel. The painful, burning sensation experienced by infected people has led to the disease being called "the fiery serpent". Other symptoms include fever, nausea, and vomiting. Female worms cause allergic reactions during blister formation as they migrate to the skin, causing an intense burning pain. Such allergic reactions produce rashes, nausea, diarrhea, dizziness, and localized edema. When the blister bursts, allergic reactions subside, but skin ulcers form, through which the worm can protrude. Only when the worm is removed is healing complete. Death of adult worms in joints can lead to arthritis and paralysis in the spinal cord.
Dracunculiasis is an infection caused by the nematode D medinensis. The larvae from D medinensis are not infective unless a molting process within the copepods occurs. This requires a fresh-water environment; thus, water ingestion is the only identified mode of transmission.
Guinea worm disease can be transmitted only by drinking contaminated water, and can be completely prevented through two relatively simple measures:
- Prevent people from drinking contaminated water containing the Cyclops copepod (water flea), which can be seen in clear water as swimming white specks.
- Drink water drawn only from sources free from contamination.
- Filter all drinking water, using a fine-mesh cloth filter like nylon, to remove the guinea worm-containing crustaceans. Regular cotton cloth folded over a few times is an effective filter.
- Filter the water through ceramic or sand filters.
- Boil the water.
- Develop new sources of drinking water without the parasites, or repair dysfunctional water sources.
- Treat water sources with larvicides to kill the water fleas.
- Prevent people with emerging Guinea worms from entering water sources used for drinking.
- Community-level case detection and containment is key. For this, staff must go door to door looking for cases, and the population must be willing to help and not hide their cases.
- Immerse emerging worms in buckets of water to reduce the number of larvae in those worms, and then discard that water on dry ground.
- Discourage all members of the community from setting foot in the drinking water source.
- Guard local water sources to prevent people with emerging worms from entering.
Dracunculiasis is diagnosed by seeing the worms emerging from the lesions on the legs of infected individuals and by microscopic examinations of the larvae.
There is no vaccine or medicine to treat or prevent Guinea worm disease. Once a Guinea worm begins emerging, the first step is to do a controlled submersion of the affected area in a bucket of water. This causes the worm to discharge many of its larvae, making it less infectious. The water is then discarded on the ground far away from any water source. Submersion results in subjective relief of the burning sensation and makes subsequent extraction of the worm easier. To extract the worm, a person must wrap the live worm around a piece of gauze or a stick. The process can be long, taking anywhere from hours to a week. Gently massaging the area around the blister can help loosen the worm. This is nearly the same treatment that is noted in the famous ancient Egyptian medical text, the Ebers papyrus from 1550 BC. Some people have said that extracting a Guinea worm feels like the afflicted area is on fire. However, if the infection is identified before an ulcer forms, the worm can also be surgically removed by a trained doctor in a medical facility.
Although Guinea worm disease is usually not fatal, the wound where the worm emerges could develop a secondary bacterial infection such as tetanus, which may be life-threatening—a concern in endemic areas where there is typically limited or no access to health care. Analgesics can be used to help reduce swelling and pain and antibiotic ointments can help prevent secondary infections at the wound site. At least in the Northern region of Ghana, the Guinea worm team found that antibiotic ointment on the wound site caused the wound to heal too well and too quickly making it more difficult to extract the worm and more likely that pulling would break the worm. The local team preferred to use something called "Tamale oil" (after the regional capital) which lubricated the worm and aided its extraction.
It is of great importance not to break the worm when pulling it out. Broken worms have a tendency to putrefy or petrify. Putrefaction leads to the skin sloughing off around the worm. Petrification is a problem if the worm is in a joint or wrapped around a vein or other important area.
Use of metronidazole or thiabendazole may make extraction easier, but also may lead to migration to other parts of the body