Ascariasis

{{Further|Helminthiasis#Signs and symptoms}}

In populations where 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. Those people who are infected with only a small number of worms usually have no symptoms.{{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}}

As larval stages travel through the body, they may cause visceral damage, peritonitis and inflammation, enlargement of the liver or spleen, and an 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.Torok E. Oxford Handbook Infect Dis and Microbiol, 2009

File:Piece of intestine, blocked by worms (16424898321).jpg

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.{{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 |pages=7970 |doi=10.4076/1757-1626-2-7970 |pmid=19830032|pmc=2740073 |s2cid=15081841 }} 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.{{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 }}

The worms lack teeth. However, they can rarely cause bowel perforations by inducing volvulus and closed-loop obstruction.{{cite web |last1=Darlington |first1=Danny |last2=Anitha |first2=Fatima Shirly |title=Ascaridial Volvulus: An Uncommon Cause of Ileal Perforation |url=https://pmc.ncbi.nlm.nih.gov/articles/PMC6055212/ |website=National Institutes of Health |access-date=17 February 2025}}

Bowel obstruction may occur in up to 0.2 per 1000 per year. 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.{{cite web |url=https://www.lecturio.com/concepts/acute-cholangitis/ | title= Acute Cholangitis

| website= The Lecturio Medical Concept Library |access-date= 27 June 2021}}{{citation needed|date=May 2021}}

Ascariasis may result in allergies to shrimp and dustmites due to the shared antigen, tropomyosin; this has not been confirmed in the laboratory.{{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 }}{{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 }}

The worms in the intestine may cause malabsorption and anorexia, which contribute to malnutrition.{{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 }} The malabsorption may be due to a loss of brush border enzymes, erosion and flattening of the villi, and inflammation of the lamina propria.{{cite book | vauthors = Stephenson LS | date = 1987 | title = The Impact of Helminth Infections on Human Nutrition. | location = London | publisher = Taylor & Francis }}

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.{{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 }}

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.

File:Ascariasis LifeCycle - CDC Division of Parasitic Diseases.png

The source of infection is from objects contaminated with fecal matter containing eggs. 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. Transmission from human to human by direct contact is impossible.{{cite web |url= https://www.cdc.gov/ncidod/dpd/parasites/ascaris/factsht_ascaris.htm#contagious |title=AscarisInfection 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 }}

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.{{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 }}

The number of 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{{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 }} and in Czechoslovakia was as high as 240–1050 eggs per litre.{{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 }}
• 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.{{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 }} A similar study in the same area showed that 73% of children working on these farms were infected with helminths, particularly Ascaris, probably as a result of exposure to the raw sewage.{{citation needed|date=March 2022}}

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 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.{{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 }}

Eggs can survive potentially for 15 years and a single worm may produce 200,000 eggs a day. They maintain their position by swimming against the intestinal flow.{{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 }}

Ascaris takes most of its nutrients from the partially digested host food in the intestine. There is some evidence that it can secrete enzyme inhibitors, presumably to protect itself from digestion by the hosts' enzymes. Children are often more severely affected.

Most 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 smears.{{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 }}

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 cm long filling defects, sometimes with a whirled appearance (bolus of worms).{{citation needed|date=July 2020}}

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. Handwashing with soap may be protective; however, there is no evidence it affects the severity of the disease. 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. This has a cost of about 2 to 3 cents per person per treatment. This is known as mass drug administration and is often carried out among school-age children.{{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 }} For this purpose, broad-spectrum benzimidazoles such as mebendazole and albendazole are the drugs of choice recommended by WHO.{{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= 978-9241547109 |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 }}

{{Further|Helminthiasis#Treatment}}

Medications that are used to kill roundworms are called ascaricides. Those recommended by the World Health Organization for ascariasis are: albendazole, mebendazole, levamisole and pyrantel pamoate. Single-dose of albendazole, mebendazole, and ivermectin are effective against ascariasis. They are effective at removing parasites and eggs from the intestines.{{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 | pages = CD010599 | date = April 2020 | issue = 4 | pmid = 32289194 | pmc = 7156140 | doi = 10.1002/14651858.CD010599.pub2 | collaboration = Cochrane Infectious Diseases Group }} Other effective agents include tribendimidine and nitazoxanide. 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.{{cn|date=December 2022}}

• Hexylresorcinol, effective in a single dose.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 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.{{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 }}
• Santonin, more toxic than hexylresorcinol and often only partly effective.{{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}}
• Oil of chenopodium, more toxic than hexylresorcinol

In some cases with severe infestation, the worms may cause bowel obstruction, requiring emergency surgery. The bowel obstruction may be due to the number of worms in the bowel or twisting of the bowel. During the surgery the worms may be manually removed.{{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 }}

It is rare for infections to be life-threatening.

File:Ascariasis world map-Deaths per million persons-WHO2012.svg

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Ascariasis is 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.{{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}}

Roughly 0.8–1.3 billion individuals are infected with this intestinal worm, primarily in Africa and Asia. About 120 to 220 million of these cases are symptomatic.

As of 2010, ascariasis caused about 2,700 directly attributable deaths, down from 3,400 in 1990. The indirectly attributable deaths due to the malnutrition link may be much higher.{{cn|date=December 2022}}

Mouse and pig animal models are used to study Ascaris infection.{{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 | title-link = ascaris suum | jstor = 3277899 }}{{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 }}

Ascariasis is more common in young animals than mature ones, with signs including unthriftiness, potbelly, rough hair coat, and slow growth.{{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}}

In pigs, the infection is caused by Ascaris suum. It is characterized by poor weight gain, leading to financial losses for the farmer.

In horses and other equines, the equine roundworm is Parascaris equorum.{{cn|date=December 2022}}

{{clear right}}

Kings of England Richard III{{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 | pages = 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 }} and Henry VIII{{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 }} both had ascariasis.

{{Reflist}}

{{offline|med}}

• Image (warning, very graphic):[http://www.sp01.com/micro/worms/imagepages/image1.htm Image 1]
• 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

}}

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