DermNet provides Google Translate, a free machine translation service. Note that this may not provide an exact translation in all languages

Author: Dr David Hille, Public Health Registrar, Department of Health, Perth, Western Australia, Australia. Copy edited by Gus Mitchell. November 2020.


Dracunculiasis — codes and concepts
open

What is dracunculiasis?

Dracunculiasis, also known as 'Guinea worm disease', is a parasitic infestation by the nematode ('roundworm') Dracunculus medinensis. It is an ancient disease documented back through millennia and is now close to eradication worldwide.

Ancient depiction of dracunculiasis

Who gets dracunculiasis?

Following eradication from many countries, dracunculiasis is now localised to rural communities in parts of sub-Saharan Africa with inadequate access to clean drinking water. Eradication initiatives have seen the annual incidence of dracunculiasis decline substantially since the 1980s. The disease was once endemic in twenty countries, with more than three million cases estimated in 1986. In 2019, cases of dracunculiasis were reported in only four countries: Angola, Chad, Cameroon, and South Sudan.

What causes dracunculiasis?

Dracunculiasis is caused by Dracunculus medinensis, a tissue parasite. Dracunculus medinensis larvae are ingested by tiny crustaceans (copepods or “water fleas”) present in a water source. People become infected after drinking contaminated water, or eating raw or incompletely cooked fish from contaminated water sources. Gastric juices kill the crustaceans, releasing the Dracunculus medinensis larvae into the small bowel.

Dracunculus medinensis larvae migrate through the bowel wall into the connective tissue, where the larvae mature and mate 2–3 months later. The male worm dies soon after mating. Pregnant adult females, which can grow to one metre in length (but only 1–2mm thick), slowly migrate to the skin surface as they mature over 12 months. The lower limb is the most common site they migrate to in about 90% of all cases.

When the skin ulcer makes contact with a fresh water source, the female worm extends from the wound to release larvae into the water. The transmission cycle then recommences.

Although it was thought there was no animal reservoir, the worms and larvae have recently been identified in dogs, with a possible cycle through them back into water sources.

Dracunculus medinensis

What are the clinical features of dracunculiasis?

When the mature female Dracunculus medinensis approaches the skin surface, a papule forms usually on the foot or lower leg below the knee. A burning pain precedes the appearance of the papule. This papule develops into a blister, which enlarges over several days before rupturing to expose the parasite. Redness, itch, swelling, and induration can occur around the blister. Often multiple worms are emerging through the skin at the same time.

Systemic symptoms including nausea, vomiting, diarrhoea, dizziness, and fever can coincide with blister development, and settle when the blister bursts. There may be an associated very itchy urticarial rash

Infection with Dracunculus medinensis

What are the complications of dracunculiasis?

Severe physical limitation of the affected limb can occur during the acute phase, lasting up to twelve weeks. A subset of patients may experience ongoing pain on mobilisation of the affected limb more than one year after removal of the parasite. Temporary or permanent disability exacerbates the pre-existing economic disadvantage affecting communities at risk of dracunculiasis.

Ulcers can become secondarily infected with bacteria, leading to cellulitis, abscesses, septic joints, and systemic sepsis, which can be rarely fatal. Tetanus may also complicate dracunculiasis.

Sometimes the worm migrates to an internal organ or surface, resulting in inflammation, compressive symptoms, or abscesses.

Lasting immunity does not develop to dracunculiasis and it is common for an individual to be infected multiple times over a lifetime in endemic areas.

How is dracunculiasis diagnosed?

Formal diagnosis can be made by parasitological examination of a worm that has been removed from the patient.

What is the treatment for dracunculiasis?

There is no specific treatment for dracunculiasis. The mature Dracunculus medinensis worm is removed by gentle traction as it emerges from the skin ulcer. This process can take several weeks. As the parasite is long and thin, it can be wrapped around a stick  ('spinning') to facilitate tension during the removal, extracting a few centimetres of worm each day taking care not to break it. Surgical removal has been advocated more recently as it is quicker, limits complications, and prevents spread.

Cleaning and dressing the wound reduces the risk of secondary bacterial infection. Covering and wrapping the wound minimises release of larvae. Topical or systemic antibiotics can be used to treat or prevent secondary bacterial infections.

How is dracunculiasis being eradicated?

Public health interventions are key to eradicating dracunculiasis from affected communities.

  • Filtering drinking water through fine cloth and adequate cooking of fish prevents the ingestion of live copepods infected with Dracunculus medinensis larvae.
  • Ensuring both people and dogs with active disease do not have contact with drinking water sources to break the transmission cycle of the parasite.
  • Provision of secure sources of drinking water such as deep bores and protected wells.
  • Education.

There is no vaccine for dracunculiasis.

See smartphone apps to check your skin.
[Sponsored content]

 

Related information

 

Bibliography

  • Centers for Disease Control and Prevention. Progress toward global eradication of dracunculiasis--January 2011-June 2012. MMWR Morb Mortal Wkly Rep. 2012;61(42):854–7. PubMed
  • Greenaway C. Dracunculiasis (guinea worm disease). CMAJ. 2004;170(4):495–500. PubMed
  • Hours M, Cairncross S. Long-term disability due to guinea worm disease. Trans R Soc Trop Med Hyg. 1994;88(5):559–60. doi:10.1016/0035-9203(94)90163-5. PubMed
  • Imtiaz R, Hopkins DR, Ruiz-Tiben E. Permanent disability from dracunculiasis. Lancet. 1990;336(8715):630. doi:10.1016/0140-6736(90)93427-q. PubMed
  • Muller R. Dracunculus and dracunculiasis. In: Dawes B (ed). Advances in Parasitology Volume 9. Academic Press, 1971: 73–151.
  • Ruiz-Tiben E, Hopkins DR, Ruebush TK, Kaiser RL. Progress toward the eradication of dracunculiasis (Guinea worm disease). Emerg Infect Dis. 1995;1(2):58–60. doi:10.3201/eid0102.950205. PubMed Central
  • Smith GS, Blum D, Huttly SR, Okeke N, Kirkwood BR, Feachem RG. Disability from dracunculiasis: effect on mobility. Ann Trop Med Parasitol. 1989;83(2):151–8. doi:10.1080/00034983.1989.11812323. PubMed
  • Watts SJ. Dracunculiasis in Africa in 1986: its geographic extent, incidence, and at-risk population. Am J Trop Med Hyg. 1987;37(1):119–25. doi:10.4269/ajtmh.1987.37.119. PubMed
  • World Health Organisation. Dracunculiasis (guinea-worm disease) Health Topic. 31 March 2019. Available at: www.who.int/health-topics/dracunculiasis [accessed 03 August 2020]
  • World Health Organisation. Dracunculiasis eradication: The disease. 30 June 2019. Available at: www.who.int/dracunculiasis/disease/en/ [accessed 04 August 2020]
  • World Health Organisation. Dracunculiasis (guinea-worm disease) Fact Sheet. 16 March 2020. Available at: www.who.int/en/news-room/fact-sheets/detail/dracunculiasis-(guinea-worm-disease) [accessed 03 August 2020]

On DermNet NZ

Other websites

Books about skin diseases