Dracunculus medinensis

Last updated

Guinea worm
Dracunculus medinensis larvae.jpg
Photomicrograph of larvae
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Nematoda
Class: Secernentea
Order: Camallanida
Family: Dracunculidae
Genus: Dracunculus
Species:
D. medinensis
Binomial name
Dracunculus medinensis
Synonyms

Gordius medinensis Linnaeus, 1758

Dracunculus medinensis (Guinea worm, dragon worm, fiery serpent [1] ) is a nematode that causes dracunculiasis, also known as guinea worm disease. [2] The disease is caused by the female [3] which, at around 80 centimetres (31 inches) in length, [4] is among the longest nematodes infecting humans. [5] The length of specimens exhibits extreme sexual dimorphism, as the longest recorded male Guinea worm is only 4 cm (1+1⁄2 in). [4]

Contents

Guinea worm is on target to be the second infectious disease of humans to be eradicated, after smallpox. It was formerly endemic to a wide swath of Africa and Eurasia; as of 2023, it remains endemic in five countries: Chad, Mali, South Sudan, Angola and Ethiopia, [6] with most cases in Chad. Guinea worm spread to Angola c. 2018, and it is now considered endemic there. Infection of domestic dogs is a serious complication in Chad.

The common name "guinea worm" is derived from the Guinea region of Western Africa.

History

Dracunculus medinensis ("little dragon from Medina") was described in Egypt as early as the 15th century BCE and possibly was the "fiery serpent" afflicting the Israelites described in the Bible. [7]

In the mid-19th century, the nematode Camallanus lacustris , which infects freshwater fish, was discovered to develop in copepods. This led Russian naturalist Alexei Pavlovich Fedchenko to discover in 1870 that D. medinensis is similarly transmitted via copepod intermediate hosts. [8]

Life cycle

General lifecycle of D. medinensis in humans Drac life cycle.png
General lifecycle of D. medinensis in humans

D. medinensis L1 larvae are found in fresh water, where they are ingested by copepods (small crustaceans) of the genus Cyclops. Within the copepod, the D. medinensis larvae develop to an infective L3 stage within 14 days. [9] When the infected copepod is ingested by a mammalian host drinking unfiltered water, the copepod is then dissolved by stomach acid and dies and the D. medinensis larvae are released and migrate through the wall of the mammalian intestine, and enter the abdominal cavity and retro-peritoneal space, where they mature into adults. After maturing and mating within the host, the males die and females (length 70–120 cm or 28–47 in) migrate in subcutaneous tissue towards the skin's surface. Around a year after the infection, the female causes the formation of a blister on the skin's surface, generally on the lower extremities, though occasionally on the hand or scrotum. When the blister ruptures, the female slowly emerges over the course of several days or weeks. [9] This causes extreme pain and irritation to the host. During those few days to hours before the worm exits the skin, the person may develop a fever, pain, or swelling in that area. When the host—in an attempt to alleviate the excruciating burning pain—submerges the affected body part in water, the female releases thousands of larvae into the water. From here, the larvae infect copepods, continuing the life cycle. [9] After the worm exits the skin the wound caused by the emerging worm often develops a secondary bacterial infection. Permanent damage can occur if the infection goes untreated around a joint. Most cases occur in areas without access to health care facilities. [10]

Animal reservoirs

In 2020, Guinea worm was found in 1507 domestic dogs in Chad, 15 in Ethiopia, and eight in Mali, as well as in 61 domestic cats in Chad and three in Ethiopia. Small numbers have also been found in wildcats and baboons. [11] These findings are a potential problem for the eradication program.

Epidemiology

A medinensis female visible under the skin of the forearm Tropical Diseases - Fig 149.png
A medinensis female visible under the skin of the forearm

D. medinensis is most commonly found in the subtropic to tropical regions, especially in India, south-west Asia (Iraq, Iran, Pakistan, etc.), and rural areas of Africa, where temperatures of 25–30 °C (77–86 °F) are best for larval development. [12] The parasite relies on people accidentally consuming microcrustaceans of the genus Cyclops (copepods), that dwell in stationary bodies of water such as ponds, large, open wells (with stairs), or rain-filled cisterns. [12] The infection occurs most during times of drought or the "dry-season" in humid climates, or during or just after the rain season in the "semiarid, wet-and-dry-climates". [12] This is due to the lower surface water of the stationary bodies of water, which are prime for the growth of the infected copepods, and main source of water for many. [12]

Pathology

D. medinensis causes dracunculiasis as a result of the emergence of the female worm, non-emergence of adult worms (usually the male), and secondary bacterial infections. [13] As it emerges to the subcutaneous tissue, the female releases a toxic chemical that may result in nausea, rash at site, diarrhea, dizziness, localized edema, reddish papule, blister, and itching. [13] Arthritis or paraplegia can result from a worm that fails to reach the skin and gets calcified in or along the joint or finds its way into the central nervous tissue. [13] Aseptic abscesses and cystic swelling can also occur when worms rupture before emerging, causing an acute inflammatory response from the host's immune system. [13]

Treatment

The female guinea worm slowly starts to emerge from the host's skin after the blister ruptures. The most common method for removing the worm involves submerging the affected body part in water to help coax the worm out. The site is then cleaned thoroughly. Then, slight pressure is applied to the worm as it is slowly pulled out of the wound. To avoid breaking the worm, pulling should stop when resistance is met. Full extraction of the female guinea worm usually takes several days. After each day's worth of extraction, the exposed portion of the worm is wrapped around a piece of rolled-up gauze or small stick to maintain tension. [14] This method of wrapping the worm around a stick or gauze is speculated to be the source for the Rod of Asclepius, the symbol of medicine. [15] Once secure, topical antibiotics are applied to the affected region, to help prevent secondary infections due to bacteria, which is then wrapped in gauze to protect the wound. The same steps are repeated each day until the whole worm has been removed from the lesion. [14]

Eradication program

Guinea worm cases by year [16]
YearReported casesCountries
1986estimated 3,500,00021 [17]
1989892,05515 [18]
1992374,20215 [18]
1995129,85219 [18]
200075,22316 [18]
200163,71716 [18]
200254,63814 [18]
200332,19313 [18]
200416,02613 [18]
200510,67412 [18]
200625,217 [lower-alpha 1] 10 [18]
20079,5859 [18]
20084,6197 [18]
20093,1905
20101,7974 [20] (6 [21] )
20111,0604 [22]
20125424 [23]
20131485 [24]
20141264 [25]
2015224 [26]
2016253 [17]
2017302 [27]
2018283 [28]
201954 [lower-alpha 2] 4 [29]
2020276 [30]
2021154 [31]
2022134 [32]

In the 1980s, the Carter Center initiated a program to eradicate the guinea worm. [33] The campaign began in 1980 at the U.S. Centers for Disease Control and Prevention. In 1984, the CDC was designated by the World Health Organization as the "Collaborating Center for Research, Training, and Eradication of D. medinensis". More than twenty countries were affected by Guinea worms in 1986. That year, WHO started the eradication program with the Carter Center leading the effort. [34] The program included education of people in affected areas that the disease was caused by larvae in drinking water, isolation and support for affected people, and – crucially – widespread distribution of net filters and pipe filters for drinking water, and education about the importance of using them.

As of 2015, the species has been reported to be near eradication. [33] The International Commission for the Certification of Dracunculus Eradication has certified 198 countries, territories, and other WHO represented areas. As of January 2015, eight countries were yet to be certified as Guinea worm-free: Angola, the Democratic Republic of the Congo, Kenya, Sudan, Chad, Ethiopia, Mali, and South Sudan; of these, only in Chad, Ethiopia, Mali, and South Sudan does D. medinensis remain endemic. [34]

See also

Explanatory notes

  1. ↑ Increase in reported cases resulted from improved reporting in southern Sudan following the peace agreement in 2005. [19]
  2. ↑ Increase over 2018 due to increased reporting, due to cash rewards in Chad for reporting cases. [29]

Related Research Articles

<i>Loa loa</i> Species of roundworm

Loa loa is a filarial (arthropod-borne) nematode (roundworm) that causes Loa loa filariasis. Loa loa actually means "worm worm", but is commonly known as the "eye worm", as it localizes to the conjunctiva of the eye. Loa loa is commonly found in Africa. It mainly inhabits rain forests in West Africa and has native origins in Ethiopia. The disease caused by Loa loa is called loiasis and is one of the neglected tropical diseases.

<span class="mw-page-title-main">Copepod</span> Subclass of crustaceans

Copepods are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic, some are benthic, several species have parasitic phases, and some continental species may live in limnoterrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds, puddles, damp moss, or water-filled recesses of plants (phytotelmata) such as bromeliads and pitcher plants. Many live underground in marine and freshwater caves, sinkholes, or stream beds. Copepods are sometimes used as biodiversity indicators.

<span class="mw-page-title-main">Carter Center</span> American nonprofit organization

The Carter Center is a nongovernmental, nonprofit organization founded in 1982 by former U.S. President Jimmy Carter. He and his wife Rosalynn Carter partnered with Emory University after his defeat in the 1980 United States presidential election. The center is located in a shared building adjacent to the Jimmy Carter Library and Museum on 37 acres (150,000 m2) of parkland, on the site of the razed neighborhood of Copenhill, two miles (3 km) from downtown Atlanta, Georgia. The library and museum are owned and operated by the United States National Archives and Records Administration, while the center is governed by a Board of Trustees, consisting of business leaders, educators, former government officials, and philanthropists.

<span class="mw-page-title-main">Onchocerciasis</span> Human helminthiasis (infection by parasite)

Onchocerciasis, also known as river blindness, is a disease caused by infection with the parasitic worm Onchocerca volvulus. Symptoms include severe itching, bumps under the skin, and blindness. It is the second-most common cause of blindness due to infection, after trachoma.

<i>Dracunculus</i> (nematode) Genus of roundworms

Dracunculus is a genus of spirurid nematode parasites in the family Dracunculidae.

<span class="mw-page-title-main">Helminthiasis</span> Any macroparasitic disease caused by helminths

Helminthiasis, also known as worm infection, is any macroparasitic disease of humans and other animals in which a part of the body is infected with parasitic worms, known as helminths. There are numerous species of these parasites, which are broadly classified into tapeworms, flukes, and roundworms. They often live in the gastrointestinal tract of their hosts, but they may also burrow into other organs, where they induce physiological damage.

<span class="mw-page-title-main">Dracunculiasis</span> Infection by the Guinea worm

Dracunculiasis, also called Guinea-worm disease, is a parasitic infection by the Guinea worm, Dracunculus medinensis. A person becomes infected by drinking water contaminated with Guinea-worm larvae that reside inside copepods. Stomach acid digests the copepod and releases the Guinea worm, which penetrates the digestive tract and escapes into the body. Around a year later, the adult female migrates to an exit site – usually the lower leg – and induces an intensely painful blister on the skin. Eventually, the blister bursts, creating a painful wound from which the worm gradually emerges over several weeks. The wound remains painful throughout the worm's emergence, disabling the affected person for the three to ten weeks it takes the worm to emerge.

<span class="mw-page-title-main">Gnathostomiasis</span> Human disease

Gnathostomiasis, also known as larva migrans profundus, is the human infection caused by the nematode Gnathostoma spinigerum and/or Gnathostoma hispidum, which infects vertebrates.

<span class="mw-page-title-main">Parasitic worm</span> Large type of parasitic organism

Parasitic worms, also known as helminths, are large macroparasites; adults can generally be seen with the naked eye. Many are intestinal worms that are soil-transmitted and infect the gastrointestinal tract. Other parasitic worms such as schistosomes reside in blood vessels.

Sparganosis is a parasitic infection caused by the plerocercoid larvae of the genus Spirometra including S. mansoni, S. ranarum, S. mansonoides and S. erinacei. It was first described by Patrick Manson in 1882, and the first human case was reported by Charles Wardell Stiles from Florida in 1908. The infection is transmitted by ingestion of contaminated water, ingestion of a second intermediate host such as a frog or snake, or contact between a second intermediate host and an open wound or mucous membrane. Humans are the accidental hosts in the life cycle, while dogs, cats, and other mammals are definitive hosts. Copepods are the first intermediate hosts, and various amphibians and reptiles are second intermediate hosts.

<span class="mw-page-title-main">Waterborne disease</span> Diseases caused by pathogenic microorganisms transmitted by waters

Waterborne diseases are conditions caused by pathogenic micro-organisms that are transmitted by water. These diseases can be spread while bathing, washing, drinking water, or by eating food exposed to contaminated water. They are a pressing issue in rural areas amongst developing countries all over the world. While diarrhea and vomiting are the most commonly reported symptoms of waterborne illness, other symptoms can include skin, ear, respiratory, or eye problems. Lack of clean water supply, sanitation and hygiene (WASH) are major causes for the spread of waterborne diseases in a community. Therefore, reliable access to clean drinking water and sanitation is the main method to prevent waterborne diseases.

<span class="mw-page-title-main">Lymphatic filariasis</span> Medical condition

Lymphatic filariasis is a human disease caused by parasitic worms known as filarial worms. Usually acquired in childhood, it is a leading cause of permanent disability worldwide, impacting over a hundred million people and manifesting itself in a variety of severe clinical pathologies While most cases have no symptoms, some people develop a syndrome called elephantiasis, which is marked by severe swelling in the arms, legs, breasts, or genitals. The skin may become thicker as well, and the condition may become painful. Affected people are often unable to work and are often shunned or rejected by others because of their disfigurement and disability.

<span class="mw-page-title-main">Neglected tropical diseases</span> Diverse group of tropical infectious diseases which are common in developing countries

Neglected tropical diseases (NTDs) are a diverse group of tropical infections that are common in low-income populations in developing regions of Africa, Asia, and the Americas. They are caused by a variety of pathogens, such as viruses, bacteria, protozoa, and parasitic worms (helminths). These diseases are contrasted with the "big three" infectious diseases, which generally receive greater treatment and research funding. In sub-Saharan Africa, the effect of neglected tropical diseases as a group is comparable to that of malaria and tuberculosis. NTD co-infection can also make HIV/AIDS and tuberculosis more deadly.

<span class="mw-page-title-main">Eradication of infectious diseases</span> Elimination of a disease from all hosts

The eradication of infectious diseases is the reduction of the prevalence of an infectious disease in the global host population to zero.

<span class="mw-page-title-main">Donald Hopkins</span> American physician (born 1941)

Donald R. Hopkins is a Bahamian American physician, a MacArthur Fellow and is the Vice President and Director of Health Programs at The Carter Center. He graduated from Morehouse College with a B.S., from the University of Chicago with a Doctor of Medicine, and from the Harvard School of Public Health with a Master of Public Health. He studied at the Institute of European Studies, University of Vienna.

<span class="mw-page-title-main">Kapoeta North County</span> County in Equatoria, South Sudan

Kapoeta North County is an administrative division of Eastern Equatoria. The principal settlement is Riwoto and the largest ethnic group are the Toposa people. The county emblem is an elephant.

This is a timeline of deworming, and specifically mass deworming.

Dr. Samuel Zanya BugriMD MSc, also known as Sam Bugri was a Ghanaian sprinter and public health official. As a sprinter, he competed in the 400 metres at the 1968 Summer Olympics and the 1972 Summer Olympics. As a healthcare professional, he had worked for many programs and organizations, including as the first Coordinator of Ghana's Guinea Worm Eradication Program. In this position he worked closely with international organizations such as the Carter Center, WHO, and UNICEF.

<span class="mw-page-title-main">Eradication of dracunculiasis</span> Permanent global eradication from humans

Eradication of dracunculiasis is an ongoing program. Dracunculiasis, or Guinea worm disease, is an infection by the Guinea worm. In 1986, there were an estimated 3.5 million cases of Guinea worm in 20 endemic nations in Asia and Africa. Ghana alone reported 180 000 cases in 1989. The number of cases has since been reduced by more than 99.999% to 14 in 2023 in six remaining endemic states: South Sudan, Chad, Mali, Ethiopia, Angola, and Central African Republic.

Hookworms are intestinal, blood-feeding, parasitic roundworms that cause types of infection known as helminthiases. Hookworm infection is found in many parts of the world, and is common in areas with poor access to adequate water, sanitation, and hygiene. In humans, infections are caused by two main species of roundworm, belonging to the genera Ancylostoma and Necator. In other animals the main parasites are species of Ancylostoma. Hookworm is closely associated with poverty because it is most often found in impoverished areas, and its symptoms promote poverty through the educational and health effects it has on children. It is the leading cause of anemia and undernutrition in developing countries, while being one of the most commonly occurring diseases among poor people. Hookworm thrives in areas where rainfall is sufficient and keeps the soil from drying out, and where temperatures are higher, making rural, coastal areas prime conditions for the parasite to breed.

References

  1. ↑ Chaudhury, Abhijit (2022). "Dracunculiasis". Textbook of Parasitic Zoonoses. Microbial Zoonoses. pp. 427–436. doi:10.1007/978-981-16-7204-0_41. ISBN   978-981-16-7203-3.
  2. ↑ Knopp, Stefanie; Amegbo, Ignace K.; Hamm, David M.; Schulz-Key, Hartwig; Banla, Meba; Soboslay, Peter T. (March 2008). "Antibody and cytokine responses in Dracunculus medinensis patients at distinct states of infection". Transactions of the Royal Society of Tropical Medicine and Hygiene . 102 (3): 277–283. doi:10.1016/j.trstmh.2007.12.003. PMID   18258273.
  3. ↑ Bimi, Langbong (2007). "Potential vector species of Guinea worm (Dracunculus medinensis) in northern Ghana". Vector-Borne and Zoonotic Diseases. 7 (3): 324–329. doi:10.1089/vbz.2006.0622. PMID   17767406.
  4. 1 2 Schmidt, Gerald D.; Roberts, Larry S. (2009). Roberts, Larry S.; Janovy, John Jr. (eds.). Foundations of Parasitology (8th ed.). McGraw-Hill. pp. 480–484. ISBN   978-0-07-128458-5.
  5. ↑ bin Saleem, Talha; Ahmed, Irfan (2006). ""Serpent" in the breast" (PDF). Journal of Ayub Medical College Abbottabad. 18 (4): 67–68. PMID   17591014.
  6. ↑ Control of Neglected Tropical Diseases team (2023). World Health Organization (ed.). Criteria for the certification of dracunculiasis eradication 2023 update. World Health Organization. pp. 9, 26. ISBN   978-92-4-007333-3.
  7. ↑ "Dracunculiasis: Historical background". who.int. World Health Organization. Archived from the original on 18 October 2014. Retrieved 27 April 2017.
  8. ↑ Anderson, Roy C. (8 February 2000). Nematode Parasites of Vertebrates: Their development and transmission. CABI. p. 1. ISBN   978-0-85199-786-5 – via Google Books.
  9. 1 2 3 "Dracunculiasis: About Guinea-Worm Disease". who.int. World Health Organization. Archived from the original on 1 November 2006. Retrieved 20 December 2015.
  10. ↑ "General information – frequently asked questions (FAQs)". Guinea Worm Disease. U.S. Centers for Disease Control and Prevention (CDC). 17 September 2020. Retrieved 24 October 2020.
  11. ↑ "Guinea worm cases fell 50% in 2020, Carter Center reports". cartercenter.org (Press release). The Carter Center. 26 January 2021.
  12. 1 2 3 4 Muller, R. (1979). "Guinea worm disease: Epidemiology, control, and treatment". Bulletin of the World Health Organization . 57 (5): 683–689. PMC   2395878 . PMID   161522.
  13. 1 2 3 4 Roberts, Larry S.; Janovy, John Jr.; Nadler, Steve (27 November 2012). Gerald D. Schmidt & Larry S. Roberts' foundations of parasitology (9th ed.). New York, NY: McGraw Hill. ISBN   978-0-07-352419-1. OCLC   812614125.
  14. 1 2 "Management of Guinea worm disease (GWD)". Parasites – Guinea Worm. cdc.gov. U.S. Centers for Disease Control (CDC). 16 March 2018. Retrieved 22 July 2018.
  15. ↑ Satin, Morton (2009). Death in the Pot: The impact of food poisoning on history. Amherst, NY: Prometheus Books. pp. 63–65. ISBN   978-1-61-592224-6 – via Google Books.
  16. ↑ "Guinea worm case totals". cartercenter.org. The Carter Center.
  17. 1 2 Martin, Jeff (11 January 2017). "Carter: Guinea worm disease reported in 3 countries in 2016". Associated Press. Archived from the original on 12 January 2017. Retrieved 11 January 2017.
  18. 1 2 3 4 5 6 7 8 9 10 11 12
    Dracunculiasis Epidemiological Data (1989-2008) (PDF). who.int (Report). World Health Organization . Retrieved 14 September 2009.
  19. ↑ Centers for Disease Control and Prevention (CDC) (17 August 2007). "Progress toward global eradication of Dracunculiasis, January 2005 – May 2007". Morbidity and Mortality Weekly Report . 56 (32). U.S. Centers for Disease Control and Prevention (CDC): 813–817. PMID   17703170 . Retrieved 16 March 2011.
  20. ↑ "Guinea worm countdown: The road to eradication". cartercenter.org. The Carter Center. Archived from the original on 6 September 2011. Retrieved 22 July 2018.
  21. ↑ "Monthly report on dracunculiasis cases, January–December 2010" (PDF). Weekly Epidemiological Record. 86 (10). WHO: 92. 4 March 2011. Retrieved 4 March 2011.
  22. ↑ "Wrap-up #209" (PDF). Guinea Worm Wrap-up. WHO Collaborating Center for Research, Training and Eradication of Dracunculiasis. No. 209. World Health Organization (WHO). 9 January 2012 – via The Carter Center (cartercenter.org).
  23. ↑ "Wrap-up #218" (PDF). Guinea Worm Wrap-up. WHO Collaborating Center for Research, Training and Eradication of Dracunculiasis. No. 218. World Health Organization (WHO). 22 April 2013. Retrieved 4 November 2022– via The Carter Center (cartercenter.org).
  24. ↑ "Wrap-up #226" (PDF). Guinea Worm Wrap-up. WHO Collaborating Center for Research, Training and Eradication of Dracunculiasis. No. 226. World Health Organization (WHO). 9 May 2014. Retrieved 4 November 2022– via The Carter Center (cartercenter.org).
  25. ↑ "126 Cases of Guinea worm disease remain worldwide". cartercenter.org (Press release). The Carter Center. 11 January 2015. Retrieved 9 May 2015.
  26. ↑ "Wrap-up #240" (PDF). Guinea Worm Wrap-up. WHO Collaborating Center for Research, Training and Eradication of Dracunculiasis. No. 240. World Health Organization (WHO). 13 May 2016. Retrieved 4 November 2022– via The Carter Center (cartercenter.org).
  27. ↑ "Announcement for 2017 Guinea worm disease case totals". cartercenter.org (Press release). The Carter Center. 19 January 2018. Archived from the original on 20 January 2018. Retrieved 22 July 2018.
  28. ↑ "28 Guinea worm cases reported in 2018". cartercenter.org (Press release). Guinea worm update. The Carter Center. 6 May 2019.
  29. 1 2 "54* cases of Guinea worm reported in 2019". cartercenter.org (Press release). The Carter Center. January 2020.
  30. ↑ "Guinea worm cases fell 50% in 2020, Carter Center reports". cartercenter.org (Press release). The Carter Center. 2021.
  31. ↑ "Wrap-up #286" (PDF). Guinea Worm Wrap-up. WHO Collaborating Center for Research, Training and Eradication of Dracunculiasis. No. 286. World Health Organization (WHO). 31 March 2022. Retrieved 29 January 2023– via The Carter Center (cartercenter.org).
  32. ↑ "Guinea worm disease reaches all-time low: Only 13* human cases reported in 2022". The Carter Center. 24 January 2023. Retrieved 29 January 2023.
  33. 1 2 "This species is close to extinction, and that's a good thing". Time . World Science Festival. 23 January 2015.
  34. 1 2 "Eradication program". Parasites – Guinea worm. U.S. Centers for Disease Control and Prevention. 2 May 2017. Retrieved 22 July 2018.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.