Last updated:
9/25/2025
Years published: 1988, 1989, 1999, 2007, 2009, 2025
NORD gratefully acknowledges Gioconda Alyea, MD (FMG), MS, National Organization for Rare Disorders, for the preparation of this report.
Dracunculiasis, also called Guinea-worm disease, is a parasitic infectious disease transmitted through contaminated drinking water, causing a painful blister from which a worm slowly emerges. It results from ingesting the parasite Dracunculus medinensis. Although it rarely causes death, infected people are often incapacitated for weeks or months. This disease predominantly affects rural, underserved and remote places in Africa that rely on open, stagnant water sources (such as ponds) for drinking-water.1,2
Ingestion of contaminated water causes the larvae to migrate from the intestines via the abdominal cavity to the tissue under the skin. The larvae mature and release a toxic substance that makes the overlying skin ulcerate. After treatment, symptoms disappear, and the worms can be safely removed from the skin.1-4
Dracunculiasis can be considered as a subtype of filariasis (a disease caused by a filarial worm) and it is included in the list of neglected tropical diseases.2,5,6
The name of the disease comes from its prevalence in the Gulf of Guinea. In the past, dracunculiasis was known as “the disease of the empty granary” because of the difficulties patients faced in going to work in fields or to school when affected by this disease.6
People infected with dracunculiasis usually do not have any symptoms for about one year after becoming infected. The symptoms start when the mature, pregnant female worm migrates through the body and approaches the skin, where she creates a painful blister, typically on the lower limbs, from which she will eventually emerge.3,4 5,7 The worm, which can grow up to 3 feet (1 meter) in length, emerges through this blister over the course of 1 to 3 weeks as a whitish filament.2,3 This process is extremely painful and is often accompanied by inflammation and secondary bacterial infections due to poor access to medical care.² The area often becomes swollen and can get infected with bacteria. The symptoms usually affect just one area of the body but can be very painful and disabling.
A few hours to days before the worm emerges, affected people may develop systemic and localized symptoms, including: 2,3,4,7
Once the blister ruptures and the worm begins to exit the body, many of the systemic symptoms tend to subside. The worm is manually extracted by slowly winding it around a stick, a process that may take several weeks. Over 90% of worms emerge from the lower extremities, typically below the knees.7
Because emergence often occurs in weight-bearing areas, the condition is extremely debilitating. Secondary bacterial infections are common and can lead to complications such as cellulitis, abscesses, tetanus, septic arthritis and systemic sepsis. Joint infections may also result in long-term deformities or contractures.7
Though rare, migrating worms may reach atypical locations including the pancreas, lungs, periorbital tissue, testes, pericardium, or spinal cord, where they can cause compressive symptoms and local abscesses.1,4 There is little to no acquired immunity to this disease, so reinfection is common, even occurring annually in some people.7
The Centers for Disease Control and Prevention (CDC) has updated information about this condition.
Dracunculiasis is caused by the parasite Dracunculus medinensis. Infection occurs when a person drinks water contaminated with tiny water fleas (copepods) that carry the immature larvae of the worm.1,4 Once inside the body, the copepods are digested, releasing the larvae. These larvae migrate to the tissues under the skin, where they grow and mature. When the adult female worm is ready to emerge, usually through the skin of the legs or feet, contact with water causes her to release a fluid containing hundreds of thousands of new larvae into the water.2,4
These larvae are then consumed by copepods in ponds and stagnant water sources, continuing the cycle. People and animals can become infected either by drinking untreated water containing these copepods or by eating aquatic animals (such as fish or frogs) that have swallowed them. Once infected, individuals can further spread the disease by entering water sources while the worm is emerging from their body.2,4,6
Transmission patterns are closely tied to seasonal changes and water access. In arid regions, infection rates tend to rise during the rainy season when surface water becomes available. In wetter areas, transmission is more common during the dry season, when people rely on stagnant water sources.2,4,6
Dracunculiasis is most common in villages where clean drinking water is unavailable. In some of these communities, up to 70% of people may be affected. The risk of infection can vary based on age, gender, occupation, and location, factors that influence how and where people collect water.4,6-8
In the mid-1980s, an estimated 3.5 million cases of dracunculiasis (Guinea worm disease) were reported across 20 countries worldwide, but the number of reported cases has been dropping gradually, and, since 2015, the number of human cases each year has remained below 100, with 22 reported in 2015 and a provisional count of 13 in 2024.2
As of now, five countries, Angola, Chad, Ethiopia, Mali, and South Sudan, remain endemic. Sudan is in the pre-certification stage, while Cameroon, which has been certified free of the disease, is dealing with cross-border transmission along its northern border with Chad. A significant challenge to eradication efforts has been the localized transmission of Guinea worm in animals, primarily domestic dogs and cats, in some of the remaining affected countries.2
The World Health Organization (WHO), working closely with national governments and other partners, continues to lead eradication efforts by offering technical support, guiding surveillance and response strategies and focusing on areas with cross-border risk or recent transmission history. WHO officially certify countries as free of dracunculiasis. This certification process is based on recommendations from the International Commission for the Certification of Dracunculiasis Eradication (ICCDE), which meets as needed to review applications and determine a country’s certification status.2
While dracunculiasis is rare in the Americas, a few cases have occurred among recent immigrants or refugees from countries where the disease is more common, such as Sudan. All cases must be reported to the WHO to help track and eliminate the disease.2,5
The diagnosis of dracunculiasis is primarily clinical and relies on the direct observation of the adult female worm emerging from the skin, typically through a painful blister or ulceration on the lower limbs (80–90% of cases). This process can last several weeks and is often accompanied by localized swelling, itching and inflammation. In some people, more than one worm may emerge simultaneously.6
Definitive diagnosis is confirmed when the worm is visibly emerging and can be gently extracted. At that point, the worm’s size should be measured, as smaller diameters (<2 mm) carry a higher risk of rupture during removal. Active larvae can sometimes be collected by immersing the exposed worm in water, and first-stage larvae identifiable by their pointed tails, can be seen under a microscope.6
In some people, the worm may die and calcify within the body before it emerges. These calcified remains can be detected incidentally on radiographic imaging, especially in soft tissues, where they appear as long, serpentine calcifications. Such findings indicate past infection rather than active disease. Notably, calcified worms have been reported during routine imaging, including mammograms and joint evaluations. These radiologic signs have been associated with chronic symptoms such as localized pain, arthritis and even asthma.6,8
Laboratory findings may support the clinical diagnosis. Peripheral eosinophilia is common, and elevated IgG4 levels may be detected through ELISA or western blot tests. While these serological tests show promising sensitivity and specificity, they are not currently used as standard diagnostic tools for confirmation or surveillance.6,8
DPDx is a website developed and maintained by CDC’s Division of Parasitic Diseases and Malaria (DPDM) that uses the Internet to assist laboratorians and pathologists in the diagnosis of parasitic diseases, both in the United States and abroad. If you are a laboratorian, pathologist, or other health professional, please click here.
Treatment
The first-line treatment involves carefully extracting the female worm once it begins to emerge from the skin. The worm must remain alive during removal, as breaking it can lead to severe inflammation and complications. The process can take several hours to days, depending on the worm’s length, which may exceed one meter. The worm is slowly pulled out by winding it around a piece of gauze or a stick, applying gentle traction. Dipping the affected limb in a bucket of water, not a drinking source, can encourage the worm to exit. Compressing the blister may also help release larvae, making extraction easier.3-6
No drug or oral medication is currently available to treat dracunculiasis. Supportive therapies include pain relievers and anti-inflammatory drugs to manage swelling and discomfort. Topical antiseptics and antibiotics are recommended to prevent secondary infections. The wound must be kept clean and covered with medicated gauze until the worm is fully removed. During this time, individuals must avoid entering any water sources used for drinking, to prevent further transmission. Tetanus vaccination is advised, although no specific vaccine for dracunculiasis exists.2,4,6
Since no medication or vaccine exists, eradication strategies focus on interrupting transmission through public health measures. These include strict case surveillance, containment, community education, and the promotion of safe water practices such as filtering drinking water with fine mesh cloths or pipe filters, boiling water, and using chlorination and larvicides to kill copepods. Communities are also encouraged to cook aquatic foods thoroughly, as infected fish or frogs may also pose a risk of transmission.4-8
The current goal is 2030 for world eradication of this disease, as set by the World Health Organization.2,5-7 In response, public health programs have expanded to include animal monitoring. Incentives have been offered for reporting infected pets, along with free veterinary care and containment support. Nonetheless, issues such as poor access to safe water, the need for regular maintenance of water infrastructure, remote village locations and limited resources continue to hinder eradication progress.2,4,7,8
Through the Guinea Worm Eradication Program (GWEP), only a handful of countries continue to have the disease. GWEP undertakes several water-related and other measures to prevent dracunculiasis.9
DPDx is the educational resource of the Centers for Disease Control and Prevention (CDC) designed for health professionals and laboratory scientists. For an overview including prevention, control and treatment visit www.cdc.gov/parasites/.
Information on current clinical trials is posted on the Internet at https://clinicaltrials.gov/. All studies receiving U.S. Government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Toll-free: (800) 411-1222
TTY: (866) 411-1010
Email: [email protected]
Some current clinical trials also are posted on the following page on the NORD website:
https://rarediseases.org/living-with-a-rare-disease/find-clinical-trials/
For information about clinical trials sponsored by private sources, contact:
https://www.centerwatch.com/
For information about clinical trials conducted in Europe, contact:
https://www.clinicaltrialsregister.eu/
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The Genetic and Rare Diseases Information Center (GARD) has information and resources for patients, caregivers, and families that may be helpful before and after diagnosis of this condition. GARD is a program of the National Center for Advancing Translational Sciences (NCATS), part of the National Institutes of Health (NIH).
View reportOrphanet has a summary about this condition that may include information on the diagnosis, care, and treatment as well as other resources. Some of the information and resources are available in languages other than English. The summary may include medical terms, so we encourage you to share and discuss this information with your doctor. Orphanet is the French National Institute for Health and Medical Research and the Health Programme of the European Union.
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