Guinea Worm Disease (Dracunculiasis)

Picture 1: CDC drawing of the Guinea worm disease life cycle.

• Guinea worm disease (GWD or Dracunculus medinensis) is a disease caused by worm-like parasites resulting in painful skin lesions when the worm emerges from them.
• When humans drink or swallow contaminated water in countries that have not eradicated the disease, a small aquatic crustacean that is a vector of the disease (copepod) is ingested and releases worm larvae that mature to result in skin lesions.
• Symptoms and signs of Guinea worm disease include fever and painful lesions (including a burning sensation), usually on the legs and/or feet with the blister-like lesions developing into ulcer-like areas where the female worms emerge.
• Diagnosis of GWD is by clinical history and observation of lesions.
• Treatment is supportive; worms may be removed carefully and lesions may require topical antibiotics. People may take Tylenol or ibuprofen for pain.
• Complications of Guinea worm disease include secondary bacterial infections and/or systemic problems like sepsis, joint destruction, and cellulitis.
• The prognosis of the disease ranges from good to poor, depending on complications.
• Water purification, education of at-risk populations, and worm removal from patients help to prevent the disease.

The definition of Guinea worm disease (also termed GWS or dracunculiasis) is an infection caused by the parasite Dracunculus medinensis.

• Part of the parasite's complex lifecycle involves development inside humans.
• When adult females are ready, usually about one year after initial infection, they come out of the skin in a painful, slow, and disabling way.
• The site where the worm emerges from the skin often becomes secondarily infected by bacteria.

Picture 2: Skin lesion on ankle with worm (white worm wound onto a matchstick); photo courtesy of the CDC.

As seen in the life cycle, humans ingest contaminated water that contains GWD larvae inside a copepod (a small aquatic crustacean that is a vector of the disease) that dies in the human gut, releasing the larvae that produce GWD. The male and female larvae reproduce. Mature fertilized female worms migrate to the skin and then out of the body and release larvae into the environment (usually in cool water).

• Due to a worldwide Guinea worm eradication program, only 25 individuals reported infections in 2016.
• These individuals occurred in three African countries: Chad, Ethiopia, and South Sudan, so travel to these countries increases the risk of getting GWD.
• Drinking water containing copepods (stagnant pools of water) will also increase the risk of contracting the disease.

The incubation period for Guinea worm disease is long -- about a year. The first signs or symptoms may include

• fever,
• itchy rash,
• nausea and/or vomiting,
• diarrhea, and
• dizziness, then leg and/or foot swelling with bumps that resemble hives, followed by a blister or lesion on the skin that has a burning feeling.

This can develop into a lesion resembling a skin ulcer and the white-colored worm emerges from the lesion when the burning painful lesions are placed in cool water. The lesions are very painful -- some are debilitating. About 90% of lesions are on the legs or feet, but the worms may emerge almost anywhere on the body.

The diagnosis of Guinea worm disease is done in almost all individuals from the patient's history and by observation of the lesion formation and/or the presence of an emerging female worm.

There is no specific drug or vaccine to treat or prevent GWD. Once the worm begins to emerge to form the lesion (encouraged by placing the lesion in cool water), the worm may be removed by slow and gentle traction. The worm may be wound up with a piece of gauze or a stick. Since some worms can be as long as one meter, worm removal may take several days or even weeks. As the worm is slowly and carefully removed, the lesion in the skin should be kept cleaned and treated with topical antibiotics if it becomes infected.

Individuals can take acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) to manage pain.

Complications of GWD may include infection of the skin and underlying tissues (cellulitis), abscesses, sepsis (can be life-threatening), joint infections, and tetanus.

If the worm breaks during removal, it can cause

• intense inflammation,
• cellulitis, and
• even more pain and swelling.

These complications can result in long-term effects such as joint destruction.

The prognosis for GWD ranges from good to poor. The successful removal of worms usually allows patients to return to their normal lifestyle. If complications such as joint deformities or joint infections develop, some patients may have chronic disabilities and cannot return to normal everyday activities.

Avoid drinking and eating any liquids or foods possibly contaminated with stagnating water in the African countries of Chad, Ethiopia, and South Sudan, where the parasites and vectors have not been eradicated. An approved larvicide, Abate, is used to kill the vectors of GWD in drinking water. However, education, water treatments, and worm removal from patients have almost eradicated the disease.

Statistics show attempts to eradicate this disease are working. The death rate is currently almost at zero and the number of new infections dropped from about 3.5 million per year in 1986 to only 25 reported diagnosed in 2016-2017. This near-eradication is due to efforts of the WHO, CDC, UNICEF, and individuals like former President Jimmy Carter, who has made the eradication of the disease a goal since 1986.