Dracunculiasis: What is Guinea Worm Disease? Diagnosis, Treatment, Prevention, and History

Epidemiology: How is Guinea Worm Disease spread? 

Dracunculus medinensis worms have been around for centuries. Calcified worms have even been discovered in Egyptian mummies [5]. 

Cases peaked in the 1980s with 3.5 million dracunculiasis cases worldwide (WHO). Almost 85% of these cases were in Africa and the rest in Asia. Preventive efforts have been so successful that the disease may be eradicated very soon. In 2020, there were only 27 human cases reported. In 2021, only 14 cases were reported in four countries – Chad, Ethiopia, Mali, and South Sudan [3,6].  

People get infected with the disease when they drink stagnant water contaminated by the Guinea worm’s larvae. Another risk factor for Guinea worm infections is the ingestion of raw or undercooked fish, frogs, and other animals [7].  

While dracunculiasis cases in humans are low, there is a new threat preventing the eradication of the disease. Countries like Chad, Ethiopia, Mali, and Cameroon are reporting a growing infection rate in dogs. According to new research, dogs are now the main reservoir for Guinea worms. They can get infected by eating fish, frogs, and other aquatic animals that may be asymptomatic carriers. Infections are more likely during the hot-dry season when people fish more often, and dogs gain access to these fish [8].

Pathogenicity and Life Cycle of the Parasite

Guinea worm larvae are carried by ‘water fleas’ – microscopic crustaceans that live on the surface of stagnant water bodies. These fleas are intermediate hosts or copepods that ingest the larvae. The larvae take about two weeks to mature, and then they can contaminate humans. 

When humans drink this unfiltered water, the intermediate hosts die. This process releases the larvae, which then penetrate the stomach and intestines of the host. In the abdomen, the larvae mature into adult worms. After copulation, the males die and the females migrate towards the skin surface through subcutaneous tissues. Adult female worms are 70 – 120 cm in length (3-4 feet), on average. 

One year after the host is infected, the female worms cause blisters on the skin, mostly on the feet. When this blister ruptures and is exposed to water, the female worm emerges from the blister, and its uterus releases thousands of larvae into the water in a white, milk-like liquid. Victims often wade into water bodies for relief from their severe burning pain, increasing disease transmission.  

The cycle continues when a copepod ingests the Guinea worm larvae [9].

Symptoms

The incubation period for Guinea worm infections can be as long as a year. The most common symptoms are painful blisters, often on the lower extremities. When these blisters come in contact with water or water bodies, female worms break the blister and emerge from them. Usually, 1-3 worms emerge together. 

The blisters are often accompanied by intense pain, a burning sensation, itchiness, slight fever, nausea, vomiting, diarrhea, and even dizziness [10]. 

To make matters worse, these open blisters are also often infected with one or more bacterial infections. If the infected individual does not receive treatment, symptoms become more severe and may lead to the presence of boils, sepsis, joint infections, and even tetanus (lockjaw). If the entire worm is not removed from the infected site, it can cause more pain and inflammation [11]. 

Diagnosis

The worm (nematode) emerges from the blister and looks like a thin white string. The blister is often painful and is often inflamed and infected by a bacterial infection. Because of this, the disease can be diagnosed visually. Since the disease is usually found in rural or remote areas, the infected individual may not have access to laboratory testing [10, 11]. 

Worms that cannot break through the skin surface often die, decompose, or calcify in the body. The calcified worms are visible on X-rays [12].

Treatment

Treating Guinea worm disease involves cleaning and disinfecting the wound. The infected area is often soaked in clean water so that worms emerge and release their larvae. This makes it easier to remove the worms from the site. 

The worms are also encouraged to exit the site by wrapping the worm around a stick and gently pulling it out. It is crucial not to break the worm since the part left behind causes severe inflammation, pain, and cellulitis [3,11]. 

Removing the worm is quite painful, and the extraction process can take weeks based on the worm’s length. Once the worms are removed, the wound area is sterilized and treated with antibiotics. 

There are no anthelmintic (anti-parasitic worm) drugs effective against dracunculiasis. Medications commonly used to treat parasitic worm infections may result in the worms migrating away from the foot or leg and exiting through other sites in the body [11,13].

Prevention: Guinea Worm Eradication

There is no vaccine to prevent dracunculiasis. However, since the 1980s, The Carter Center, together with WHO and UNICEF, has been aggressively executing the Guinea Worm Eradication Program – a global campaign to eliminate dracunculiasis. 

According to the WHO, the most successful preventive strategies include: 

• Surveillance and inspections in high-risk areas
• Preventing further contamination of drinking water by isolating infected individuals in case containment centers
• Regular cleaning and bandaging of infected regions to prevent worms from emerging and releasing larvae
• Improving the quality and access to drinking water 
• Treating water bodies with larvicide to kill copepods
• Educating people in high-risk areas about filtering their water with a fine-mesh cloth, chlorination, or boiling before drinking 

If a country reports zero transmission over 14 consecutive months, it is considered to have interrupted transmission. Countries can get certified as ‘dracunculiasis-free’ if they do not have any reported disease transmission and actively conduct surveillance for three consecutive years. 

An international certification team (ICT) verifies the claims and files a report with the International Commission for the Certification of Dracunculiasis Eradication (ICCDE). The ICCDE is an independent committee of experts established by WHO in 1995. 

The successes of national dracunculiasis eradication programs are largely due to grassroots campaigns. The GWEP selected many groups of village volunteers to identify infected individuals. The volunteers also helped slow disease transmission by isolating infected individuals in local case containment centers. They also educated their communities and distributed water filters [3,14].