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Pinworm (parasite)

herpes parasite, pinworm parasite activity
The pinworm species Enterobius vermicularis, also known as threadworm in the United Kingdom and Australasia or seatworm, is a parasitic worm It is a nematode roundworm and a common intestinal parasite or helminth, especially in humans The medical condition associated with pinworm infestation is known as pinworm infection enterobiasis a type of helminthiasis or less precisely as oxyuriasis in reference to the family Oxyuridae

Other than human, Enterobius vermicularis were reported from bonnet macaque Other species seen in primates include Enterobius buckleyi in Orangutan and Enterobius anthropopitheci in chimpanzee Enterobius vermicularis is common in human children and transmitted via the faecal-oral route Humans are the only natural host of Enterobius vermicularis Enterobius gregorii, another human species is morphologically indistinguishable from Enterobius vermicularis except the spicule size Throughout this article, the word "pinworm" refers to Enterobius In British usage, however, pinworm refers to Strongyloides, while Enterobius is called threadworm


  • 1 Classification
  • 2 Morphology
  • 3 Life cycle
  • 4 Infection
  • 5 Distribution
  • 6 See also
  • 7 Notes
  • 8 References
  • 9 External links


The pinworm genus Enterobius is a type of roundworm nematode, and three species of pinworm have been identified with certainty Humans are hosts only to Enterobius vermicularis formerly Oxyurias vermicularis Chimpanzees are host to Enterobius anthropopitheci, which is morphologically distinguishable from the human pinworm Hugot 1983 claims another species affects humans, Enterobius gregorii, which is supposedly a sister species of E vermicularis, and has a slightly smaller spicule ie, sexual organ Its existence is controversial, however; Totkova et al 2003 consider the evidence to be insufficient, and Hasegawa et al 2006 contend that E gregorii is a younger stage of E vermicularis Regardless of its status as a distinct species, E gregorii is considered clinically identical to E vermicularis


Two female pinworms next to a ruler: The markings are 1 mm apart

The adult female has a sharply pointed posterior end, is 8 to 13 mm long, and 05 mm thick The adult male is considerably smaller, measuring 2 to 5 mm long and 02 mm thick, and has a curved posterior end The eggs are translucent and have a surface that adheres to objects The eggs measure 50 to 60 μm by 20 to 30 μm, and have a thick shell flattened on one side The small size and colourlessness of the eggs make them invisible to the naked eye, except in barely visible clumps of thousands of eggs Eggs may contain a developing embryo or a fully developed pinworm larva The larvae grow to 140–150 μm in length

Life cycle

Life cycle of E vermicularis showing the stages inside and outside of the human body

The entire life cycle, from egg to adult, takes place in the human gastrointestinal tract of a single host, from about 2–4 weeks or about 4–8 weeks

The life cycle begins with eggs being ingested The eggs hatch in the duodenum ie, first part of the small intestine The emerging pinworm larvae grow rapidly to a size of 140 to 150 μm, and migrate through the small intestine towards the colon During this migration, they moult twice and become adults Females survive for 5 to 13 weeks, and males about 7 weeks The male and female pinworms mate in the ileum ie, last part of the small intestine, whereafter the male pinworms usually die, and are passed out with stool The gravid female pinworms settle in the ileum, caecum ie, beginning of the large intestine, appendix and ascending colon, where they attach themselves to the mucosa and ingest colonic contents

Almost the entire body of a gravid female becomes filled with eggs The estimations of the number of eggs in a gravid female pinworm range from about 11,000 to 16,000 The egg-laying process begins about five weeks after initial ingestion of pinworm eggs by the human host The gravid female pinworms migrate through the colon towards the rectum at a rate of 12 to 14 cm per hour They emerge from the anus, and while moving on the skin near the anus, the female pinworms deposit eggs either through 1 contracting and expelling the eggs, 2 dying and then disintegrating, or 3 bodily rupture due to the host scratching the worm After depositing the eggs, the female becomes opaque and dies The female emerges from the anus to obtain the oxygen necessary for the maturation of the eggs


Main article: Enterobiasis

E vermicularis causes the medical condition enterobiasis, whose primary symptom is itching in the anal area


The pinworm has a worldwide distribution, and is the most common helminth ie, parasitic worm infection in the United States, western Europe, and Oceania In the United States, a study by the Center of Disease Control reported an overall incidence rate of 114% among children Pinworms are particularly common in children, with prevalence rates in this age group having been reported as high as 61% in India, 50% in England, 39% in Thailand, 37% in Sweden, and 29% in Denmark Finger sucking has been shown to increase both incidence and relapse rates, and nail biting has been similarly associated Because it spreads from host to host through contamination, pinworms are common among people living in close contact, and tends to occur in all people within a household The prevalence of pinworms is not associated with gender, nor with any particular social class, race, or culture Pinworms are an exception to the tenet that intestinal parasites are uncommon in affluent communities
A fossilized nematode egg was detected in 240 million-year-old fossil dung, showing that parasitic pinworms already infested pre-mammalian cynodonts The earliest known instance of the pinworms associated with humans is evidenced by pinworm eggs found in human coprolites carbon dated to 7837 BC found in western Utah

See also

  • Roundworm, hookworm, ringworm similarly named parasites and fungi


  1. ^ a b Hasegawa et al 2005
  2. ^ a b Hasegawa et al 1998
  3. ^ a b c Hasegawa et al 2006
  4. ^ a b Totkova et al 2003
  5. ^ Encyclopædia Britannica
  6. ^ Merriam-Webster: Enterobiasis
  7. ^ Merriam-Webster: Oxyuriasis
  8. ^ CP,, Arjun October 2015 "A Study of Gastrointestinal Parasites in Bonnet Macaques Macaca radiata of Pookode, Wayanad, Kerala" Zoos' Print Magazine Zoo Outreach Organization Retrieved 20 October 2015 
  9. ^ Foitová, Ivona; Civáňová, Kristína; Baruš, Vlastimil; Nurcahyo, Wisnu 2014-07-01 "Phylogenetic relationships between pinworms Nematoda: Enterobiinae parasitising the critically endangered orang-utan, according to the characterisation of molecular genomic and mitochondrial markers" Parasitology Research 113 7: 2455–2466 doi:101007/s00436-014-3892-y ISSN 1432-1955 PMID 24880237 
  10. ^ Panidis, Stavros; Paramythiotis, Daniel; Panagiotou, Dimitris; Batsis, Georgios; Salonikidis, Spyridon; Kaloutsi, Vassiliki; Michalopoulos, Antonios 2011-01-01 "Acute appendicitis secondary to Enterobius vermicularis infection in a middle-aged man: a case report" Journal of Medical Case Reports 5: 559 doi:101186/1752-1947-5-559 ISSN 1752-1947 PMC 3245485  PMID 22128765 
  11. ^ CP, Arjun October 2015 "A Study of Gastrointestinal Parasites in Bonnet Macaque Macaca radiata of Pookode, Wayanad, Kerala" PDF Zoos' Print 10 – via Zoos' Print 
  12. ^ Vanderkooi 2000, p B-152 & B-225
  13. ^ NCBI taxonomy database 2009
  14. ^ a b dpdx 2009
  15. ^ Hugot 1983
  16. ^ a b c d e f Gutiérrez 2005, p 354
  17. ^ a b c d e f g h i j k l m Cook 1994, p 1159
  18. ^ a b Cook et al 2009, p 1516
  19. ^ a b c d e f g h i j Burkhart & burkhart 2005, p 837
  20. ^ a b c d Garcia 1999, p 246
  21. ^ a b c Caldwell 1982, p 307
  22. ^ a b c d Gutiérrez 2005, p 355
  23. ^ "Enterobiasis leads to itching" Retrieved 20 August 2011 
  24. ^ http://wwwbetterhealthvicgovau/bhcv2/bhcarticlesnsf/pages/Worms_pinworms
  25. ^ Cook 1994, p 1160
  26. ^ "Scientists find 240 million-year-old parasite that infected mammals’ ancestor : accessed 8 December 2014


  • Hasegawa H, Ikeda Y, Fujisaki A, et al December 2005 "Morphology of chimpanzee pinworms, Enterobius Enterobius anthropopitheci Gedoelst, 1916 Nematoda: Oxyuridae, collected from chimpanzees, Pan troglodytes, on Rubondo Island, Tanzania" The Journal of Parasitology 91 6: 1314–7 doi:101645/GE-569R1 PMID 16539010 
  • "Pinworm" Encyclopædia Britannica Retrieved 8 April 2009 
  • "Enterobiasis" Merriam-Webster's Medical Dictionary Merriam-Webster Retrieved 8 April 2009 
  • "Oxyuriasis" Merriam-Webster's Medical Dictionary Merriam-Webster Retrieved 8 April 2009 
  • Totkova A, Klobusicky M, Holkova R, Valent M 2003 "Enterobius gregorii—reality or fiction" PDF Bratislavské Lekárske Listy 104 3: 130–3 PMID 12940699 Archived from the original PDF on 10 September 2011 
  • "Enterobius" NCBI taxonomy database National Center for Biotechnology Information, US National Library of Medicine 2009 Retrieved 8 April 2009 
  • "Enterobiasis" DPDx Division of Parasitic Diseases, Centers for Disease Control and Prevention Retrieved 8 April 2009 
  • Nakano T, Okamoto M, Ikeda Y, Hasegawa H December 2006 "Mitochondrial cytochrome c oxidase subunit 1 gene and nuclear rDNA regions of Enterobius vermicularis parasitic in captive chimpanzees with special reference to its relationship with pinworms in humans" Parasitology Research 100 1: 51–7 doi:101007/s00436-006-0238-4 PMID 16788831 
  • Hugot JP 1983 "" Annales de Parasitologie Humaine et Comparée in French 58 4: 403–4 doi:101051/parasite/1983584403 PMID 6416131 
  • Hasegawa H, Takao Y, Nakao M, Fukuma T, Tsuruta O, Ide K February 1998 "Is Enterobius gregorii Hugot, 1983 Nematoda: Oxyuridae a distinct species" The Journal of Parasitology 84 1: 131–4 doi:102307/3284542 JSTOR 3284542 PMID 9488350 
  • Gutiérrez, Yezid 2000 Diagnostic pathology of parasitic infections with clinical correlations PDF Second ed Oxford University Press pp 354–366 ISBN 0-19-512143-0 Retrieved 21 August 2009 
  • Cook, Gordon C; Zumla, Alimuddin I 2009 Manson's tropical diseases 22nd ed Saunders Elsevier pp 1515–1519 ISBN 978-1-4160-4470-3 Retrieved 18 November 2009 
  • "B80: Enterobiasis" International Statistical Classification of Diseases and Related Health Problems ICD 10th Revision World Health Organization 2007 Retrieved 5 December 2009 
  • Cook GC September 1994 "Enterobius vermicularis infection" Gut 35 9: 1159–62 doi:101136/gut3591159 PMC 1375686  PMID 7959218 
  • Garcia, Lynne Shore 2009 Practical guide to diagnostic parasitology American Society for Microbiology pp 246–247 ISBN 1-55581-154-X Retrieved 5 December 2009 
  • Burkhart CN, Burkhart CG October 2005 "Assessment of frequency, transmission, and genitourinary complications of enterobiasis pinworms" International Journal of Dermatology 44 10: 837–40 doi:101111/j1365-4632200402332x PMID 16207185 
  • Caldwell JP February 1982 "Pinworms Enterobius Vermicularis" Canadian Family Physician 28: 306–9 PMC 2306321  PMID 21286054 
  • Vanderkooi M 2000 Village Medical Manual 5th ed 

External links

  • Enterobius vermicularis image library at DPD

herpes parasite, herpes parasite cleanse, pinworm parasite activity, pinworm parasite medication, pinworm parasite photos, pinworm parasite treatment

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Pinworm (parasite)

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