Dracunculiasis (Guinea-worm disease)

4 November 2019

Dracunculiasis is a crippling parasitic disease caused by infection with Dracunculus medinensis, a long thread-like worm. Infection occurs when people drink water contaminated with parasite-infected water fleas.

During the 1980s, dracunculiasis was endemic in 20 countries. Mali has reported zero human cases since 2016; the last case was reported in November 2015. Ethiopia reported its last human case in December 2017.

When the eradication campaign began in 1986, there were an estimated 3.5 million cases.

UNICEF
12 year old Zenabu Mesele, fetches water from the pond. "I came here to fetch water. The pond is called Werenka. What do you use the water for? For vegetables, for the cattle. We don’t use it to drink or for food. What do you use for drinking water? From piped water."

Guinea-worm disease is transmitted exclusively by drinking stagnant water contaminated with tiny water fleas that carry infective guinea-worm larvae.

Guinea-worm disease affects people in rural, deprived and isolated communities who depend mainly on open surface water sources such as ponds for drinking water.
People swallow the infected water fleas when drinking contaminated water. The water fleas are killed in the stomach but the ineffective larvae are liberated. They then penetrate the wall of the intestine and migrate through the body. The fertilized female worm (which measures 60–100 cm long) migrates under the skin tissues until it reaches its exit point, usually at the lower limbs, forming a blister or swelling from which it eventually emerges. The worm takes 10–14 months to emerge after infection.

Jane Hahn
A parasitologist, examining a Guinea worm in Bongor, Chad.

The worm responsible for Dracunculiasis takes 10–14 months to emerge after infection.

About a year after infection, a painful blister forms – 90% of the time on the lower leg – and one or more worms emerge accompanied by a burning sensation.

Jane Hahn
The Chari River, on whose banks dogs mysteriously began to be infected with Guinea worms in 2012.

Larvae of the Dracunculus medinensis parasite are released in water.

To soothe the burning pain, patients often immerse the infected part of the body in water. The worm(s) then releases thousands of larvae (baby worms) into the water. These larvae reach the infective stage after being ingested by tiny crustaceans or copepods, also called water fleas.

On contact with water, the worm discharges hundreds of thousands of larvae into the water.

Dracunculiasis is rarely fatal, but infected people become non-functional for weeks.

Guinea-worm disease does not kill, but infected people become non-functional for months. Since the peak transmission period often coincides with the agricultural season, fields are left untended and food production level goes down. In Mali, guinea-worm disease is called "the disease of the empty granary." As adults lie sick, older children must take on the household chores and miss months of schooling. Smaller children might miss vital vaccinations.

Successful implementation of preventive strategies have driven dracunculiasis to the verge of eradication.

A successful eradication programme for guinea-worm disease comprises several preventive strategies such as: ensuring wider access to safe drinking-water supplies, filtration of drinking water to prevent infection, intense surveillance and control to detect every case within 24 hours of the emergence of the worm(s), treatment of ponds with the larvicide temephos that kills the water fleas and promoting health education and behaviour change.

Early detection of dracunculiasis is vital to contain the disease.

Early case detection (when the patient feels the initial pain) is vital to contain the disease. There are thousands of village volunteers in the remaining endemic countries who are trained to find new cases, take care of them and report them to the area supervisor.

There is no vaccine to prevent Guinea-worm disease, nor is there any medication to treat patients.

Once a new case is identified, the volunteer must clean, disinfect and bandage the wound to protect it from secondary infections. The volunteer returns every other day to gradually pull the worm out, a few painful inches each day.

The Carter Center
School children learn about how to protect themselves from contracting Guinea worm disease.

Health education about dracunculiasis is key to stop transmission cycle.

Health education about the disease is a key responsibility of the village volunteers. They convince infected people to stay away from drinking water sources until worms are fully extracted. They explain to patients and their families how to use cloth filters to make drinking water safer.

Dracunculiasis-Lake-chad-JS

Implementing vector control contributes to the interruption of Guinea-worm disease transmission

During the transmission season, contaminated ponds can be treated with the larvicide temephos which kills the infective water fleas.

WHO established the International Commission for the Certification of Dracunculiasis Eradication in 1995 to certify the elimination of guinea-worm disease.

WHO is the only organization mandated to certify countries as free of the disease following recommendations made by the ICCDE. The ICCDE currently comprises 9 public health experts. The Commission meets as and when necessary to evaluate the status of transmission in countries applying for certification of dracunculiasis eradication and to recommend whether a particular country should be certified as free of transmission.