View source for Ascariasis

{{short description|Disease caused by the parasitic roundworm Ascaris lumbricoides}}
{{about|the infection|the organism|Ascaris}}
{{distinguish|text=[[acariasis]], a mite infection, principally of skin}}
{{Infobox medical condition
| name          = Ascariasis
| image         = Ascaris infection in X-ray image- Duedenal worms - in the first portion of the bowel after the stomach (South Africa) (16238958958).jpg
| caption       = High number of [[ascaris]] worms – visible as black tangled mass – are filling the [[duodenum]], the first portion of the bowel after the stomach, of this South African patient (X-ray image with barium as contrast medium).
| field         = [[Infectious disease (medical specialty)|Infectious disease]]
| symptoms      = Abdominal swelling, abdominal pain, [[diarrhea]], shortness of breath<ref name=Dold2011 />
| complications =
| onset         =
| duration      =
| causes        = Ingestion of ''[[Ascaris]]'' eggs<ref name=Hagel2010 />
| risks         =
| diagnosis     =
| differential  =
| prevention    = Improved [[sanitation]], [[handwashing]]<ref name=Dold2011 />
| treatment     =
| medication    = [[Albendazole]], [[mebendazole]], [[levamisole]], [[pyrantel pamoate]]<ref name=Hagel2010/>
| prognosis     =
| frequency     = 762 million (2015)<ref name=GBD2015Pre>{{cite journal | vauthors = Vos T, Allen C, Arora M, Barber RM, Bhutta ZA, Brown A, etal | collaboration = GBD 2015 Disease and Injury Incidence and Prevalence Collaborators | title = Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015 | journal = Lancet | volume = 388 | issue = 10053 | pages = 1545–1602 | date = October 2016 | pmid = 27733282 | pmc = 5055577 | doi = 10.1016/S0140-6736(16)31678-6 }}</ref>
| deaths        = 2,700 (2015)<ref name=GBD2015De>{{cite journal | vauthors = Wang H, Naghavi M, Allen C, Barber RM, Bhutta ZA, Carter A, etal | collaboration = GBD 2015 Mortality and Causes of Death Collaborators | title = Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980-2015: a systematic analysis for the Global Burden of Disease Study 2015 | journal = Lancet | volume = 388 | issue = 10053 | pages = 1459–1544 | date = October 2016 | pmid = 27733281 | pmc = 5388903 | doi = 10.1016/s0140-6736(16)31012-1 }}</ref>
}}
<!-- Definition and symptoms -->

'''Ascariasis''' is a disease caused by the parasitic [[roundworm]] ''[[Ascaris lumbricoides]]''.<ref name="Dold2011">{{cite journal |vauthors=Dold C, Holland CV |date=July 2011 |title=Ascaris and ascariasis |journal=Microbes and Infection |volume=13 |issue=7 |pages=632–7 |doi=10.1016/j.micinf.2010.09.012 |hdl=2262/53278 |pmid=20934531 |hdl-access=free}}</ref><ref name=":0">{{Cite journal |last=Anorue |first=Chioma Ogochukwu |last2=Anyanwu |first2=Ihuoma N. |last3=Chiamah |first3=Ogochukwu C. |date=2023 |title=A cross sectional study on the prevalence of ascariasis among school children; a case study of ikwo, ebonyi state nigeria |url=http://pharmacoj.com/ojs/index.php/Medph/article/view/38 |journal=Medical and Pharmaceutical Journal |pages=75–82 |doi=10.55940/medphar202338|doi-access=free }}</ref> Infections have no symptoms in more than 85% of cases, especially if the number of worms is small.<ref name=":0" /> Symptoms increase with the number of worms present and may include [[shortness of breath]] and fever at the beginning of the disease.<ref name="Dold2011" /> These may be followed by symptoms of abdominal swelling, abdominal pain, and [[diarrhea]].<ref name="Dold2011" /> Children are most commonly affected, and in this age group the infection may also cause poor weight gain, [[malnutrition]], and learning problems.<ref name="Dold2011" /><ref name="Hagel2010" /><ref name="WHO2013">{{cite web|title=Soil-transmitted helminth infections Fact sheet N°366|url=https://www.who.int/mediacentre/factsheets/fs366/en/|website=World Health Organization|date=June 2013|url-status=live|archive-url=https://web.archive.org/web/20140221013137/http://www.who.int/mediacentre/factsheets/fs366/en/|archive-date=2014-02-21}}</ref>

<!-- Cause and Mechanism -->
Infection occurs by ingesting food or drink contaminated with ''Ascaris'' eggs from feces.<ref name=Hagel2010 /> The eggs hatch in the [[intestine]]s, the larvae burrow through the gut wall, and migrate to the lungs via the blood.<ref name=Hagel2010 /> There they break into the [[Pulmonary alveolus|alveoli]] and pass up the [[Vertebrate trachea|trachea]], where they are coughed up and may be swallowed.<ref name=Hagel2010 /> The larvae then pass through the stomach a second time into the intestine, where they become adult worms.<ref name=Hagel2010 /> It is a type of [[soil-transmitted helminthiasis]] and part of a group of diseases called [[helminthiases]].<ref name=NTD2017>{{cite web|title=Neglected Tropical Diseases|url=https://www.cdc.gov/globalhealth/ntd/diseases/index.html|website=cdc.gov|access-date=28 November 2014|date=June 6, 2011|url-status=live|archive-url=https://web.archive.org/web/20141204084219/http://www.cdc.gov/globalhealth/ntd/diseases/index.html|archive-date=4 December 2014}}</ref>

<!-- Prevention and Treatment -->
Prevention is by improved [[sanitation]], which includes improving access to toilets and proper disposal of [[feces]].<ref name=Dold2011 /><ref>{{cite journal | vauthors = Ziegelbauer K, Speich B, Mäusezahl D, Bos R, Keiser J, Utzinger J | title = Effect of sanitation on soil-transmitted helminth infection: systematic review and meta-analysis | journal = PLOS Medicine | volume = 9 | issue = 1 | article-number = e1001162 | date = January 2012 | pmid = 22291577 | pmc = 3265535 | doi = 10.1371/journal.pmed.1001162 | doi-access = free }}</ref> Handwashing with soap appears protective.<ref name=Fung2009>{{cite journal | vauthors = Fung IC, Cairncross S | title = Ascariasis and handwashing | journal = Transactions of the Royal Society of Tropical Medicine and Hygiene | volume = 103 | issue = 3 | pages = 215–22 | date = March 2009 | pmid = 18789465 | doi = 10.1016/j.trstmh.2008.08.003 }}</ref> In areas where more than 20% of the population is affected, treating everyone at regular intervals is recommended.<ref name=Dold2011 /> Reoccurring infections are common.<ref name=Hagel2010 /><ref>{{cite journal | vauthors = Jia TW, Melville S, Utzinger J, King CH, Zhou XN | title = Soil-transmitted helminth reinfection after drug treatment: a systematic review and meta-analysis | journal = PLOS Neglected Tropical Diseases | volume = 6 | issue = 5 | article-number = e1621 | year = 2012 | pmid = 22590656 | pmc = 3348161 | doi = 10.1371/journal.pntd.0001621 | doi-access = free }}</ref> There is no [[vaccine]].<ref name=Hagel2010 /> Treatments recommended by the [[World Health Organization]] are the medications [[albendazole]], [[mebendazole]], [[levamisole]], or [[pyrantel pamoate]].<ref name=Hagel2010>{{cite journal | vauthors = Hagel I, Giusti T | title = Ascaris lumbricoides: an overview of therapeutic targets | journal = Infectious Disorders Drug Targets | volume = 10 | issue = 5 | pages = 349–67 | date = October 2010 | pmid = 20701574 | doi = 10.2174/187152610793180876 }}</ref> Other effective agents include [[tribendimidine]] and [[nitazoxanide]].<ref name=Hagel2010 />

<!-- Epidemiology -->
About 0.8 to 1.2 billion people globally have ascariasis, with the most heavily affected populations being in [[sub-Saharan Africa]], [[Latin America]], and Asia.<ref name=Dold2011 /><ref name=Kei2010 /><ref name=Fen2012>{{cite journal | vauthors = Fenwick A | title = The global burden of neglected tropical diseases | journal = Public Health | volume = 126 | issue = 3 | pages = 233–236 | date = March 2012 | pmid = 22325616 | doi = 10.1016/j.puhe.2011.11.015 }}</ref> This makes ascariasis the most common form of [[soil-transmitted helminthiasis]].<ref name=Kei2010>{{cite journal | vauthors = Keiser J, Utzinger J | title = The drugs we have and the drugs we need against major helminth infections | journal = Advances in Parasitology | volume = 73 | pages = 197–230 | year = 2010 | pmid = 20627144 | doi = 10.1016/s0065-308x(10)73008-6 | isbn = 978-0-12-381514-9 }}</ref> As of 2010 it caused about 2,700 deaths a year, down from 3,400 in 1990.<ref name=Loz2012>{{cite journal | vauthors = Lozano R, Naghavi M, Foreman K, Lim S, Shibuya K, Aboyans V, etal | s2cid = 1541253 | title = Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010 | journal = Lancet | volume = 380 | issue = 9859 | pages = 2095–128 | date = December 2012 | pmid = 23245604 | doi = 10.1016/S0140-6736(12)61728-0 | pmc = 10790329 | url = https://zenodo.org/record/2557786 | hdl = 10536/DRO/DU:30050819 | hdl-access = free }}</ref> Another type of ''Ascaris'' infects pigs.<ref name=Dold2011 /> Ascariasis is classified as a [[neglected tropical disease]].<ref name=NTD2017/>
{{TOC limit|3}}

== Signs and symptoms ==
{{Further|Helminthiasis#Signs and symptoms}}

In populations where [[Helminthiasis|worm infections]] are widespread, it is common to find that most people are infected by a small number of worms, while a small number of people are heavily infected. This is characteristic of many types of worm infections.<ref name="Dold2011" /><ref name="Anderson1" /> Those people who are infected with only a small number of worms usually have no symptoms.<ref>{{cite web |url= https://www.cdc.gov/parasites/ascariasis/gen_info/faqs.html | title= Parasites - Ascariasis | website= C.D.C, U.S. Department of Health & Human Services | date= 20 October 2020 |access-date= 27 June 2021}}</ref>

=== Migrating larvae ===
As larval stages travel through the body, they may cause visceral damage, [[peritonitis]] and [[inflammation]], enlargement of the [[liver]] or [[spleen]], and an [[pneumonitis|inflammation of the lungs]]. Pulmonary manifestations take place during larval migration and may present as [[Loeffler's syndrome]], a transient respiratory illness associated with blood eosinophilia and pulmonary infiltrates with radiographic shadowing.<ref>Torok E. Oxford Handbook Infect Dis and Microbiol, 2009</ref>

=== Intestinal blockage ===
[[File:Piece of intestine, blocked by worms (16424898321).jpg|thumb|Piece of intestine, blocked by worms, surgically removed from a three-year-old boy in South Africa<ref>Fincham, J., Dhansay, A. (2006). [http://www.susana.org/en/resources/library/details/2110 Worms in SA's children – MRC Policy Brief] {{webarchive|url=https://web.archive.org/web/20150402123849/http://www.susana.org/en/resources/library/details/2110 |date=2015-04-02 }}. Nutritional Intervention Research Unit of the South African Medical Research Council, South Africa</ref>]]

The worms can occasionally cause intestinal blockage when large numbers get tangled into a bolus or they may migrate from the small intestine, which may require surgery.<ref>{{cite journal |last1=Yetim |first1=I |last2=Ozkan |first2=OV |last3=Semerci |first3=E |last4=Abanoz |first4=R |title=Rare cause of intestinal obstruction, Ascaris lumbricoides infestation: two case reports. |journal=Cases Journal |date=17 June 2009 |volume=2 |page=7970 |doi=10.4076/1757-1626-2-7970 |pmid=19830032|pmc=2740073 |s2cid=15081841 }}</ref> More than 796 ''A. lumbricoides'' worms weighing up to {{Convert|550|g|oz|abbr=on}} were recovered at autopsy from a two-year-old South African girl. The worms had caused torsion and gangrene of the [[ileum]], which was interpreted as the cause of death.<ref>{{cite journal | vauthors = Baird JK, Mistrey M, Pimsler M, Connor DH | title = Fatal human ascariasis following secondary massive infection | journal = The American Journal of Tropical Medicine and Hygiene | volume = 35 | issue = 2 | pages = 314–8 | date = March 1986 | pmid = 3953945 | doi = 10.4269/ajtmh.1986.35.314 | url = http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1411&context=publichealthresources | url-access = subscription }}</ref>

The worms lack teeth. However, they can rarely cause bowel perforations by inducing [[volvulus]] and closed-loop obstruction.<ref>{{cite journal |last1=Darlington |first1=Danny |last2=Anitha |first2=Fatima Shirly |title=Ascaridial Volvulus: An Uncommon Cause of Ileal Perforation |journal=Iranian Journal of Medical Sciences |date=2018 |volume=43 |issue=4 |pages=432–435 |pmid=30046214 |pmc=6055212 }}</ref>

=== Bowel obstruction ===
[[Bowel obstruction]] may occur in up to 0.2 per 1000 per year.<ref name="Dold2011" /> A worm may block the [[ampulla of Vater]], or go into the [[main pancreatic duct]], resulting in acute [[pancreatitis]] with raised serum levels of [[amylase]] and [[lipase]]. Occasionally, a worm can travel through the biliary tree and even into the [[gallbladder]], causing acute [[cholangitis]] or acute [[cholecystitis]].<ref>{{cite web |url=https://www.lecturio.com/concepts/acute-cholangitis/ | title= Acute Cholangitis
| website= The Lecturio Medical Concept Library |access-date= 27 June 2021}}</ref>{{citation needed|date=May 2021}}

=== Allergies ===
Ascariasis may result in [[allergy|allergies]] to shrimp and [[dustmite]]s due to the shared [[antigen]], [[tropomyosin]]; this has not been confirmed in the laboratory.<ref name="Berman2012">{{Citation |title= Taxonomic Guide to Infectious Diseases: Understanding the Biologic Classes of Pathogenic Organisms |publisher= Academic Press |first= Jules J. |last= Berman | name-list-style = vanc |year= 2012 |isbn= 978-0-12-415895-5 |url= https://books.google.com/books?id=m7vT6i3xmC4C&pg=PA151 |page= 151 |url-status= live |archive-url= https://web.archive.org/web/20130530034719/http://books.google.com/books?id=m7vT6i3xmC4C&pg=PA151 |archive-date= 2013-05-30 }}</ref><ref name="pmid18486690">{{cite journal | vauthors = Reddy A, Fried B | title = Atopic disorders and parasitic infections | journal = Advances in Parasitology | volume = 66 | pages = 149–91 | date = 2008 | pmid = 18486690 | doi = 10.1016/S0065-308X(08)00203-0 | url = https://books.google.com/books?id=G8av9Gs284MC&pg=PA165 | veditors = Rollinson D, Hay SI | isbn = 978-0-08-087900-0 | url-access = subscription }}</ref>

=== Malnutrition ===
The worms in the intestine may cause [[malabsorption]] and [[Anorexia (symptom)|anorexia]], which contribute to [[malnutrition]].<ref name="Hall2">{{cite journal | vauthors = Hall A, Hewitt G, Tuffrey V, de Silva N | title = A review and meta-analysis of the impact of intestinal worms on child growth and nutrition | journal = Maternal & Child Nutrition | volume = 4 | issue = Suppl 1 | pages = 118–236 | date = April 2008 | pmid = 18289159 | doi = 10.1111/j.1740-8709.2007.00127.x | pmc = 6860651 | url = http://westminsterresearch.wmin.ac.uk/4665/1/Hall_et_al_2008_final.pdf }}</ref> The malabsorption may be due to a loss of brush border enzymes, erosion and flattening of the villi, and inflammation of the [[lamina propria]].<ref name="Stephenson1">{{cite book | vauthors = Stephenson LS | date = 1987 | title = The Impact of Helminth Infections on Human Nutrition. | location = London | publisher = Taylor & Francis }}</ref>

=== Others ===
''Ascaris'' have an aversion to some general anesthetics and may exit the body, sometimes through the mouth, when an infected individual is put under [[general anesthesia]].<ref>{{cite journal | vauthors = Wu ML, Jones VA | title = Ascaris lumbricoides | journal = Archives of Pathology & Laboratory Medicine | volume = 124 | issue = 1 | pages = 174–5 | date = January 2000 | pmid = 10629158 | doi = 10.5858/2000-124-0174-AL | url = https://meridian.allenpress.com/aplm/article/124/1/174/452377/Ascaris-lumbricoides | url-access = subscription }}</ref>

== Cause ==
<gallery mode="packed" widths="360" heights="220">
File:Ascaris Larva.png|The larva of ''Ascaris lumbricoides'' developing in the egg
File:Ascaris lumbricoides.jpeg|''Ascaris lumbricoides'' adult worms (with measuring tape for scale)
File:Ascaris lumbricoides adult worms.png|''Ascaris lumbricoides'' adult worms
File:Ascaris egg, incubation process.png|''Ascaris'' egg, incubation process: The ''Ascaris'' egg incubation process consists of placing the egg in a controlled environment, at {{Convert|26|C|F|abbr=on}} during 28 days, in acidic conditions. This process allows for the evaluation of an egg to determine if it is viable or not.
</gallery>
[[File:Ascariasis LifeCycle - CDC Division of Parasitic Diseases.png|thumb|upright=1.3|''Ascaris'' life cycle: Adult worms (1) live in the lumen of the small intestine. A female may produce approximately 200,000 eggs per day, which are passed with feces (2). Unfertilized eggs may be ingested but are not infective. Fertile eggs embryonate and become infective after 18 days to several weeks (3), depending on the environmental conditions (optimum: moist, warm, shaded soil). After infective eggs are swallowed (4), the larvae hatch (5), invade the intestinal mucosa, and are carried via the portal, then systemic circulation and/or lymphatics to the lungs. The larvae mature further in the lungs (6) (10 to 14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed (7). Upon reaching the small intestine, they develop into adult worms (8). Between 2 and 3 months are required from ingestion of the infective eggs to oviposition by the adult female. Adult worms can live 1 to 2 years.]]

=== Transmission ===
The source of infection is from objects contaminated with fecal matter containing eggs.<ref name=Hagel2010 /> Ingestion of infective eggs from soil contaminated with human feces or contaminated vegetables and water is the primary route of infection. Infectious eggs may occur on objects such as hands, money, and furniture.<ref name=Hagel2010 /> Transmission from human to human by direct contact is impossible.<ref>{{cite web |url= https://www.cdc.gov/ncidod/dpd/parasites/ascaris/factsht_ascaris.htm#contagious |title=''Ascaris''Infection Fact Sheet|url-status=live |archive-url= https://web.archive.org/web/20100531191820/http://www.cdc.gov/ncidod/dpd/parasites/ascaris/factsht_ascaris.htm#contagious |archive-date=2010-05-31 |date=2019-04-24 }}</ref>

Transmission comes through municipal recycled wastewater into crop fields. This is quite common in emerging industrial economies and poses serious risks for local crop sales and exports of contaminated vegetables. A 1986 outbreak of ascariasis in Italy was traced to irresponsible wastewater recycling used to grow [[Balkan]] vegetable exports.<ref>{{cite book | vauthors = Pawlowski ZS, Schultzberg K | chapter =Ascariasis and sewage in Europe| editor = Block JC |title=Epidemiological Studies of Risks Associated With the Agricultural Use of Sewage Sludge: Knowledge and Needs (EUR) |publisher=Elsevier Science Pub Co |year=1986|pages=83–93 |isbn=978-1-85166-035-3 }}</ref>

The number of [[ovum|ova]] (eggs) in [[sewage]] or in crops that were irrigated with raw or partially treated sewage, is a measure of the degree of ascariasis incidence.{{citation needed|date=May 2021}} For example:
* In a study published in 1992, municipal wastewater in Riyadh, Saudi Arabia, detected over 100 eggs per litre of wastewater<ref>{{cite journal | vauthors = Bolbol AS | title = Risk of contamination of human and agricultural environment with parasites through reuse of treated municipal wastewater in Riyadh, Saudi Arabia | journal = Journal of Hygiene, Epidemiology, Microbiology, and Immunology | volume = 36 | issue = 4 | pages = 330–7 | year = 1992 | pmid = 1300348 }}</ref> and in Czechoslovakia was as high as 240–1050 eggs per litre.<ref>{{cite journal | vauthors = Horák P | title = Helminth eggs in the sludge from three sewage treatment plants in Czechoslovakia | journal = Folia Parasitologica | volume = 39 | issue = 2 | pages = 153–7 | year = 1992 | pmid = 1644362 }}</ref>
* In one field study in Marrakech, Morocco, where raw sewage is used to fertilize crop fields, ''Ascaris'' eggs were detected at the rate of 0.18 eggs/kg in potatoes, 0.27 eggs/kg in turnip, 4.63 eggs/kg in mint, 0.7 eggs/kg in carrots, and 1.64 eggs/kg in radish.<ref>{{cite journal | vauthors = Habbari K, Tifnouti A, Bitton G, Mandil A | title = Helminthic infections associated with the use of raw wastewater for agricultural purposes in Beni Mellal, Morocco | journal = Eastern Mediterranean Health Journal | volume = 5 | issue = 5 | pages = 912–21 | date = September 1999 | doi = 10.26719/1999.5.5.912 | pmid = 10983530 | doi-access = free }}</ref> A similar study in the same area showed that 73% of children working on these farms were infected with [[helminth]]s, particularly ''Ascaris'', probably as a result of exposure to the raw sewage.{{citation needed|date=March 2022}}

=== Lifecycle ===
The first appearance of eggs in stools is 60–70 days. In larval ascariasis, symptoms occur 4–16 days after infection. The final symptoms are gastrointestinal discomfort, colic and vomiting, fever, and observation of live worms in stools. Some patients may have pulmonary symptoms or neurological disorders during the migration of the larvae. There are generally few or no symptoms. A [[bolus (digestion)|bolus]] of worms may obstruct the intestine; migrating larvae may cause [[pneumonitis]] and [[eosinophilia]]. Adult worms have a lifespan of 1–2 years which means that individuals may be infected all their lives as worms die and new worms are acquired.<ref name=Anderson1>{{cite book | vauthors = Anderson RS, May RM | author-link2 = Robert May, Baron May of Oxford | date = 1991 | title = Infectious diseases of humans. Dynamics and control. | location = Oxford | publisher = Oxford Scientific Publications }}</ref>

Eggs can survive potentially for 15 years and a single worm may produce 200,000 eggs a day.<ref name=Hagel2010 /> They maintain their position by swimming against the intestinal flow.<ref name=Crompton1>{{cite book | vauthors = Crompton DW, Pawlowski ZS | date = 1985 | chapter = Life history and development of ''Ascaris lumbricoides'' and the persistence of human ascariasis. | title = Ascariasis and its public health significance. | veditors = Crompton DW, Nesheim MC, Pawlowski ZS | location = London | publisher = Taylor & Francis }}</ref>

== Mechanism ==
''Ascaris'' takes most of its nutrients from the partially digested host food in the intestine. There is some evidence that it can secrete [[enzyme inhibitor]]s, presumably to protect itself from digestion by the hosts' enzymes. Children are often more severely affected.<ref name=Dold2011 />

== Diagnosis ==
Most [[diagnosis|diagnoses]] are made by identifying the appearance of the [[worm]] or eggs in feces. Due to the large quantity of eggs laid, diagnosis can generally be made using only one or two [[fecal smear]]s.<ref>{{cite book |last=Grove |first=David I | name-list-style = vanc |date=1990 |title=A history of human helminthology |location=Wallingford |publisher=CAB International |pages=1–848 |isbn=0-85198-689-7 }}</ref>
The diagnosis is usually incidental when the host passes a worm in the stool or vomit. The eggs can be seen in a smear of fresh feces examined on a glass slide under a microscope and there are various techniques to concentrate them first or increase their visibility, such as the ether sedimentation method or the [[Kato technique]]. The eggs have a characteristic shape: they are oval with a thick, mamillated shell (covered with rounded mounds or lumps), measuring  35–50 micrometer in diameter and 40–70 in length. During pulmonary disease, larvae may be found in fluids aspirated from the lungs. White blood cell counts may demonstrate peripheral [[eosinophilia]]; this is common in many parasitic infections and is not specific to ascariasis. On X-ray, 15–35&nbsp;cm long filling defects, sometimes with a whirled appearance (bolus of worms).{{citation needed|date=July 2020}}

== Prevention ==
Prevention is by improved access to sanitation which includes the use of properly functioning and clean toilets by all community members as one important aspect.<ref name=Dold2011 /> Handwashing with soap may be protective; however, there is no evidence it affects the severity of the disease.<ref name=Fung2009 /> Eliminating the use of untreated human faeces as [[fertilizer]] is also important.{{citation needed|date=May 2021}}

In areas where more than 20% of the population is affected treating everyone is recommended.<ref name=Dold2011 /> This has a cost of about 2 to 3 cents per person per treatment.<ref name=Dold2011 /> This is known as [[mass drug administration]] and is often carried out among school-age children.<ref>{{cite journal | vauthors = Mascarini-Serra L | title = Prevention of Soil-transmitted Helminth Infection | journal = Journal of Global Infectious Diseases | volume = 3 | issue = 2 | pages = 175–82 | date = April 2011 | pmid = 21731306 | pmc = 3125032 | doi = 10.4103/0974-777X.81696 | doi-access = free }}</ref> For this purpose, broad-spectrum [[benzimidazole]]s such as [[mebendazole]] and [[albendazole]] are the drugs of choice recommended by [[WHO]].<ref>{{cite book |author= WHO |year= 2006 |title= Preventive Chemotherapy in Human Helminthiasis : Coordinated Use of Anthelminthic Drugs in Control Interventions: a Manual for Health Professionals and Programme Managers |url= http://whqlibdoc.who.int/publications/2006/9241547103_eng.pdf |publisher= WHO Press, World Health Organization, Geneva, Switzerland |pages= 1–61 |isbn= 978-92-4-154710-9 |url-status= live |archive-url= https://web.archive.org/web/20130228145914/http://whqlibdoc.who.int/publications/2006/9241547103_eng.pdf |archive-date= 2013-02-28 }}</ref>

== Treatment ==
{{Further|Helminthiasis#Treatment}}

=== Medications ===
Medications that are used to kill roundworms are called [[ascaricide]]s. Those recommended by the World Health Organization for ascariasis are: [[albendazole]], [[mebendazole]], [[levamisole]] and [[pyrantel pamoate]].<ref name=Hagel2010 /> Single-dose of albendazole, mebendazole, and [[ivermectin]] are effective against ascariasis. They are effective at removing parasites and eggs from the intestines.<ref>{{cite journal | vauthors = Conterno LO, Turchi MD, Corrêa I, Monteiro de Barros Almeida RA | title = Anthelmintic drugs for treating ascariasis | journal = The Cochrane Database of Systematic Reviews | volume = 2020 | article-number = CD010599 | date = April 2020 | issue = 4 | pmid = 32289194 | pmc = 7156140 | doi = 10.1002/14651858.CD010599.pub2 | collaboration = Cochrane Infectious Diseases Group }}</ref> Other effective agents include [[tribendimidine]] and [[nitazoxanide]].<ref name=Hagel2010 /> Pyrantel pamoate may induce intestinal obstruction in a heavy worm load. Albendazole is contraindicated during pregnancy and children under two years of age. [[Thiabendazole]] may cause migration of the worm into the [[esophagus]], so it is usually combined with [[piperazine]].{{citation needed|date=May 2021}}

Piperazine is a flaccid paralyzing agent that blocks the response of ''Ascaris'' muscle to acetylcholine, which immobilizes the worm. It prevents migration when treatment is accomplished with weak drugs such as thiabendazole. If used by itself, it causes the worm to be passed out in the feces and may be used when worms have caused blockage of the intestine or the biliary duct.{{citation needed|date=July 2020}}

[[Corticosteroids]] can treat some of the symptoms, such as inflammation.{{citation needed|date=December 2022}}

==== Other medications ====
* [[Hexylresorcinol]], effective in a single dose.<ref name="Holt11th">Holt, Jr Emmett L, McIntosh Rustin: Holt's Diseases of Infancy and Childhood: A Textbook for the Use of Students and Practitioners. Appleton and Co, New York, 11th edition</ref> During the 1940s this compound, as Crystoids brand pills, was the treatment of choice; patients were instructed not to chew the Crystoids to prevent burns to the mucous membranes. A saline cathartic would be administered several hours later.<ref>{{cite report | last = Most | first = Harry | title=Clinical Aspects and Treatment of the More Common Intestinal Parasites of Man | journal=Veterans Administration Technical Bulletins 1946 & 1947 Series 10| date= July 9, 1947 | number= TB 10–33 | pages=8–9 | publication-date = January 1948 | publisher = U.S. Veterans Administration | location = Washington, DC | type= none | name-list-style = vanc | url=https://books.google.com/books?id=uJWxEzwqRiMC }}</ref>
* [[Santonin]], more toxic than hexylresorcinol<ref name="Holt11th" /> and often only partly effective.<ref>{{cite book|url=https://books.google.com/books?id=iDNy0XxGqT8C&pg=PA91|title=The evolution of drug discovery: from traditional medicines to modern drugs|date=2011|publisher=Wiley-VCH|isbn=978-3-527-32669-3|edition=1st |location=Weinheim|page=91|last1=Ravina|first1=Enrique | name-list-style = vanc |url-status=live|archive-url=https://web.archive.org/web/20170908213540/https://books.google.com/books?id=iDNy0XxGqT8C&pg=PA91|archive-date=2017-09-08}}</ref>
* Oil of [[chenopodium]], more toxic than hexylresorcinol<ref name="Holt11th" />

=== Surgery ===
In some cases with severe infestation, the worms may cause [[bowel obstruction]], requiring emergency surgery.<ref name=Hef2009 /> The bowel obstruction may be due to the number of worms in the bowel or [[volvulus|twisting of the bowel]].<ref name=Hef2009 /> During the surgery the worms may be manually removed.<ref name=Hef2009>{{cite journal | vauthors = Hefny AF, Saadeldin YA, Abu-Zidan FM | title = Management algorithm for intestinal obstruction due to ascariasis: a case report and review of the literature | journal = Ulusal Travma ve Acil Cerrahi Dergisi = Turkish Journal of Trauma & Emergency Surgery | volume = 15 | issue = 3 | pages = 301–5 | date = May 2009 | pmid = 19562557 }}</ref>

== Prognosis ==
It is rare for infections to be life-threatening.<ref name=Dold2011 />

== Epidemiology ==
[[File:Ascariasis world map-Deaths per million persons-WHO2012.svg|thumb|upright=1.3|Ascariasis deaths per million persons in 2012 {{Div col|small=yes|colwidth=10em}}{{legend|#ffff20|0-1}}{{legend|#d85010|1-2}}{{legend|#d02010|2-3}}{{div col end}}]]
[[File:Ascariasis world map - DALY - WHO2004.svg|thumb|upright=1.3|[[Disability-adjusted life year]] for ascariasis per 100,000&nbsp;inhabitants in 2004{{Div col|small=yes|colwidth=10em}}
{{legend|#b3b3b3|no data}}
{{legend|#ffff65|less than 10}}
{{legend|#fff200|10-20}}
{{legend|#ffdc00|20-30}}
{{legend|#ffc600|30-40}}
{{legend|#ffb000|40-50}}
{{legend|#ff9a00|50-60}}
{{legend|#ff8400|60-80}}
{{legend|#ff6e00|80-100}}
{{legend|#ff5800|100-120}}
{{legend|#ff4200|120-140}}
{{legend|#ff2c00|140-150}}
{{legend|#cb0000|more than 150}}
{{div col end}}]]

=== Regions ===
Ascariasis is [[Endemic (epidemiology)|common]] in tropical regions as well as subtropical and regions that lack proper sanitation. It is rare to find traces of the infection in developed or urban regions.<ref>{{cite web |url= https://www.cdc.gov/parasites/ascariasis/biology.html |title= Parasites - Ascariasis | website= CDC, U.S. Department of Health & Human Services |date= 19 July 2019 | access-date= 27 June 2021}}</ref>

=== Infection estimates ===
Roughly 0.8–1.3 billion individuals are infected with this intestinal worm, primarily in Africa and Asia.<ref name="Dold2011" /><ref name="Hagel2010" /><ref name="Fen2012" /> About 120 to 220 million of these cases are symptomatic.<ref name="Dold2011" />

=== Deaths ===
As of 2010, ascariasis caused about 2,700 directly attributable deaths, down from 3,400 in 1990.<ref name="Loz2012" /> The indirectly attributable deaths due to the malnutrition link may be much higher.{{citation needed|date=December 2022}}

== Research ==
Mouse and pig animal models are used to study ''Ascaris'' infection.<ref>{{cite journal | vauthors = Howes HL | title = Anthelmintic studies with pyrantel. II. Prophylactic activity in a mouse-ascaris suum test model | journal = The Journal of Parasitology | volume = 57 | issue = 3 | pages = 487–93 | date = June 1971 | pmid = 5090955 | doi = 10.2307/3277899 | jstor = 3277899 }}</ref><ref>{{cite journal | vauthors = Lichtensteiger CA, DiPietro JA, Paul AJ, Neumann EJ, Thompson L | title = Persistent activity of doramectin and ivermectin against Ascaris suum in experimentally infected pigs | journal = Veterinary Parasitology | volume = 82 | issue = 3 | pages = 235–41 | date = April 1999 | pmid = 10348103 | doi = 10.1016/S0304-4017(99)00018-7 }}</ref>

== Other animals ==
Ascariasis is more common in young animals than mature ones, with signs including unthriftiness, potbelly, rough hair coat, and slow growth.<ref name="eXtension2">{{cite web|url=http://www.extension.org/pages/10319/parasites:-ascarids|title=Parasites:Ascarids|date=September 27, 2011|website=eXtension|archive-url=https://web.archive.org/web/20141109073736/http://www.extension.org/pages/10319/parasites%3A-ascarids#.VF8KCt6FarJ|archive-date=9 November 2014|url-status=live|access-date=9 November 2014}}</ref>

In pigs, the infection is caused by ''[[Ascaris suum]].'' It is characterized by poor weight gain, leading to financial losses for the farmer.<ref name="Dold2011" />

In horses and other equines, the equine roundworm is ''[[Parascaris equorum]].''{{citation needed|date=December 2022}}
{{clear right}}

==Society and culture==
Kings of England Richard III<ref>{{cite journal | vauthors = Mitchell PD, Yeh HY, Appleby J, Buckley R | s2cid = 42898331 | title = The intestinal parasites of King Richard III | journal = Lancet | volume = 382 | issue = 9895 | page = 888 | date = September 2013 | pmid = 24011545 | doi = 10.1016/S0140-6736(13)61757-2 | hdl = 2381/31491 | url = https://figshare.com/articles/journal_contribution/10193159 | hdl-access = free }}</ref> and Henry VIII<ref>{{cite web |url=http://www.livescience.com/39392-king-richard-iii-roundworm-infection.html |title=Infected and Hunched: King Richard III Was Crawling with Roundworms |website=[[Live Science]] |date=3 September 2013 |access-date=2017-01-07 |url-status=live |archive-url=https://web.archive.org/web/20170109191935/http://www.livescience.com/39392-king-richard-iii-roundworm-infection.html |archive-date=2017-01-09 }}</ref> both had ascariasis.

== References ==
{{Reflist}}

== External links ==

{{offline|med}}
* Image (warning, very graphic):[http://www.sp01.com/micro/worms/imagepages/image1.htm Image 1]
* [[Centers for Disease Control and Prevention|CDC]] [https://web.archive.org/web/20130710103131/http://www.dpd.cdc.gov/DPDx/ ''DPDx Parasitology Diagnostic Web Site'']
{{Medical condition classification and resources
| ICD11 = {{ICD11|1F62}}
| ICD10 = {{ICD10|B|77||b|65}}
| ICD9 = {{ICD9|127.0}}
| OMIM = 604291
| DiseasesDB = 934
| MedlinePlus = 000628
| eMedicineSubj = article
| eMedicineTopic = 212510
| MeshID = D001196
}}
{{Helminthiases}}
{{Portal bar|Biology|Medicine}}

[[Category:Helminthiases]]
[[Category:Foodborne illnesses]]
[[Category:Ascaridomorpha]]
[[Category:Tropical diseases]]
[[Category:Conditions diagnosed by stool test]]
[[Category:Wikipedia medicine articles ready to translate]]
[[Category:Wikipedia infectious disease articles ready to translate]]
[[Category:Zoonoses]]