[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fxLN3MUwXCdr5RPjwZYIDpOj8CHyjOmngWTgoKXPtZbg":3,"$fYqucCuS8DfQ6xCsZYIGWLzlTA5Ef2hl7HiKvw3MSwPw":32,"$f3Ft0rKFJHppdzE-vuveecxx1BUcg9iOlMLtyzf_MJDg":60},[4,8,12,16,20,24,28],{"title":5,"slug":6,"path":7},"About Microbeonline.com","about-microbeonline-com","\u002Fabout-microbeonline-com\u002F",{"title":9,"slug":10,"path":11},"About Me","about-me","\u002Fabout-microbeonline-com\u002Fabout-me\u002F",{"title":13,"slug":14,"path":15},"Advertise with Us","advertise-us","\u002Fadvertise-us\u002F",{"title":17,"slug":18,"path":19},"Privacy Policy","privacy-policy","\u002Fprivacy-policy\u002F",{"title":21,"slug":22,"path":23},"Abbreviations","abbreviations","\u002Fabbreviations\u002F",{"title":25,"slug":26,"path":27},"Microbes","microbes","\u002Fmicrobes\u002F",{"title":29,"slug":30,"path":31},"Books","recommended-books","\u002Frecommended-books\u002F",{"type":33,"data":34},"blog",{"slug":35,"title":36,"description":37,"seoTitle":38,"seoDescription":38,"author":39,"createdDate":40,"lastUpdatedDate":41,"draft":42,"category":43,"image":38,"body":44,"faq":45,"tags":58,"related":59},"ascaris-lumbricoides-life-cycle-pathogenesis-and-lab-diagnosis","Ascaris lumbricoides: Life Cycle, Pathogenesis, Treatment, and Laboratory Diagnosis","Why does the world's most common worm infection cause everything from a cough to a surgical emergency? Complete Ascaris lumbricoides life cycle, the four mechanisms of disease, treatment, and egg morphology.",null,"Acharya Tankeshwar","2022-04-11","2026-06-30",false,"parasitology","An 18-year-old presents with severe abdominal pain, guarding, and silent bowel sounds — the picture of an acute abdomen. The working diagnosis is complicated appendicitis. At laparotomy, the surgeon finds not an inflamed appendix but a tangled mass of roundworms completely obstructing the small bowel.\n\nThis is the same organism that, in most of the roughly one billion people infected with it worldwide, causes no symptoms at all and in some, causes nothing more than a transient cough weeks before any intestinal symptoms appear. *Ascaris lumbricoides* is unusual among parasites in how dramatically its presentation depends on three variables: how many worms are present, where exactly they happen to be at a given moment, and how long the infection has been established. Understanding all three is what separates recognising a straightforward, asymptomatic worm carrier from recognising a surgical emergency caused by the same organism.\n\n*Ascaris lumbricoides*, commonly known as “roundworm” is the **largest nematode parasitizing man**. The adult worms are cylindrical, with a tapering anterior end. When freshly passed from the intestine, *Ascaris* is light brown or pink in color, but gradually changes to white. *Ascaris* infection (ascariasis) is the most common human worm infection with nearly 1 billion cases every year.\n\n## Life Cycle\n\nInfection in humans is acquired through **ingestion of** the **embryonated eggs** from **contaminated soil.**\n\n> Ascaris lumbricoides is one of the soil-transmitted helminths, other most commons soil-transmitted helminths are whipworm (Trichuris trichiura), and hookworm (Ancylostoma duodenale and Necator americanus.\n\nOn ingestion, the embryonated eggs **hatch in the stomach and duodenum**, where the larvae actively penetrate the intestinal wall. They are then carried to the **right heart** via the hepatic portal circulation. Larvae within the eggs undergo one or possibly two molts prior to penetration of the intestinal wall.\n\n![ - Life cycle of Ascaris lumbricoides (Image source: CDC)](\u002Fblogs\u002FLife-Cycle-of-Ascaris-Lumbricoides.jpg)Figure: Life cycle of Ascaris lumbricoides (Image source: CDC)\n\nFrom the right heart, they are carried into the pulmonary circulation, where they are filtered out by the capillaries. After approximately 10 days in the lung, the larvae **break into the alveoli,** migrate via the bronchi until they **reach** the trachea and **pharynx**, and then are **swallowed**.\n\nThe **worms then mature and mate in the intestine**, with the eventual production of eggs, which are passed in the stool. The stool may contain both fertilized and unfertilized eggs. After 2 weeks, fertilized eggs become infective if they are in warm, moist soil. Fertilized eggs may remain viable for months or even years.\n\n> This entire cycle of egg ingestion to egg passage takes about 8-12 weeks.\n\n## Pathogenesis\n\n### Transmission\n\nPeople get an infection with *Ascaris* by swallowing embryonated eggs of *Ascaris* with raw vegetables cultivated on soil fertilized by human excreta or by drinking water contaminated with mature eggs of *Ascaris*.\n\nThe major burden of this parasitic disease lies in under-developed or developing countries of tropical and sub-tropical regions where sanitation is not good. Children and early adolescents are mostly affected as they spend most of their time playing in the contaminated fields (in many such countries people defecate in open areas and maybe using the feces of an infected person as fertilizer).\n\n### Clinical Disease\n\n**Ascariasis** is the disease caused by *Ascaris lumbricoides*. Pathogenesis caused by *Ascaris* infections is attributed to\n\n1. The host immune response,\n2. Effects of larval migration,\n3. Mechanical effects of the adult worms, and\n4. Nutritional deficiencies due to the presence of adult worms.\n\n## Why Four Mechanisms, One Organism\n\nThe four mechanisms listed above are not four different diseases — they are four different consequences of where the worm is and what it is doing at a given point in its life cycle, and understanding this progression makes the whole clinical picture click into place:\n\n- **During larval migration** (the first \\~10 days, while larvae are travelling through the lungs), the host immune system reacting to migrating larvae produces the allergic, pulmonary picture — Löffler's syndrome.\n- **Once adult worms are established in the intestine**, their sheer physical presence (especially in heavy infections) is what produces the mechanical effects — from minor cramping to, at the extreme, frank obstruction.\n- **Throughout the infection**, regardless of worm location, adult worms are consuming nutrients the host needs — this is a continuous drain rather than a discrete event, which is why nutritional impairment is the dominant problem in children with long-standing, untreated infection rather than in someone who clears the infection quickly.\n- **At any point**, the host's immune system can react to the worm's body fluids (ascaron) with allergic phenomena, independent of where the worm physically is.\n\nThe clinical lesson: a patient's presentation depends entirely on which of these four processes is dominant at the time they're seen — a child with chronic malnutrition and stunting, a returning traveller with a cough and eosinophilia, and a surgical patient with bowel obstruction may all have the exact same underlying organism, simply caught at different points in its relationship with the host.\n\n**Host Immune Response**\n\nVarious allergic manifestations such as fever, urticaria, angioneurotic edema, wheezing, and conjunctivitis are seen when the host immune cells react with the toxic body fluid (ascaron) of the adult worms.\n\n**Effects of Larval Migration**\n\nThe worms are restless wanderers. The migrating larvae may cause inflammatory and hypersensitivity reactions in the lungs. Allergic inflammatory reactions to migrating larvae may involve other organs such as liver and kidneys. Loeffler’s syndrome is caused by migrating larvae.\n\n#### Loeffler’s syndrome\n\nReinfection and subsequent larval migration cause intense tissue reactions in some individuals. There may be pronounced tissue reaction around the larvae in the liver and lungs, with infiltration of eosinophils, macrophages, and epitheloid cells. This condition, also known as Ascaris pneumonitis is accompanied by an allergic reaction consisting of dyspnea, a dry or productive cough, wheezing or coarse rales, fever, **transient eosinophilia**, and a chest X-ray suggestive of viral pneumonia. Examinations of sputum or gastric washings may reveal larvae.\n\n## Mechanical Effects of Adult Worms\n\nThe presence of adult worms in the intestine usually causes no difficulties, sometimes producing only colicky cramps and loss of appetite, unless the worm burden is heavy. However, *Ascaris* adults are genuinely restless wanderers capable of migrating to locations well beyond their usual habitat in the jejunum, and this wandering behaviour is responsible for the most serious complications of this infection.\n\n**Intestinal obstruction.** In heavy infections, a mass of tangled worms can completely obstruct the small bowel — this is the most common serious mechanical complication, particularly in children with high worm burdens. Presentation ranges from partial obstruction (colicky pain, distension, managed initially with nasogastric decompression, IV fluids, and antibiotics) to complete obstruction, which requires surgical intervention after initial resuscitation. Surgical exploration may reveal the obstructing worm mass, and an incidental appendectomy or repair of associated anomalies (such as a Meckel's diverticulum) is sometimes performed at the same time.\n\n**Biliary and pancreatic migration.** Adult worms can migrate from the small intestine into the ampulla of Vater and from there into the common bile duct or pancreatic duct, causing biliary colic, cholangitis, acute pancreatitis, or obstructive jaundice. This is a particularly important complication to recognise because **a single dose of albendazole can paradoxically worsen the situation** — paralysing the worm in the intestine can prompt other worms to migrate toward the biliary tree through the ampulla of Vater in response. For this reason, when biliary or pancreatic migration is suspected or confirmed, endoscopic removal (via ERCP) is often preferred over relying on anthelmintic therapy alone.\n\n**Other reported sites of worm migration and complications:** appendicitis (worms migrating into the appendiceal lumen), hepatic abscess, gallbladder ascariasis, and rarely, perforation of the bowel wall or a Meckel's diverticulum, with associated peritonitis.\n\n**Why this matters clinically:** Any patient from or with travel history to an endemic area who presents with an acute abdomen, biliary colic, or pancreatitis of uncertain cause should have ascariasis considered in the differential — especially since, as already noted in the Clinical Disease overview, light to moderate worm burdens are often otherwise asymptomatic, meaning the surgical complication may be the first sign of infection.\n\n**Nutritional Deficiencies due to the Presence of Adult Worms**\n\nAdult worms rob the host of its nutrition and may cause malnutrition and night blindness (due to vitamin A deficiency). In children, particularly those younger than 5 years, there may be severe nutritional impairment related to worm burden which may cause malnutrition, stunting, and impairment in cognitive ability among others.\n\n## Laboratory Diagnosis\n\n### Microscopy and Staining\n\nIn the larval migration phase of infection, diagnosis can be made by finding the **larvae in sputum** or **gastric washings**; however, this is not a common finding.\n\nDuring the intestinal phase, the **diagnosis is made by finding the eggs (unfertilized or fertilized) or adult worms in the stool**. The eggs are most easily seen on a direct wet mount or a wet preparation of the concentration sediment. Zinc-sulfate flotation concentration method or [formal-ether concentration method](\u002Fformal-ether-sedimentation-techniques\u002F) is commonly used to concentrate the stool sediment.\n\n#### Morphology of Eggs\n\nHuman excreta may contain both fertilized and unfertilized eggs of *Ascaris.* If the person is harboring only females, unfertilized eggs are only seen in the stool.\n\n![ - Various types of eggs ofAscaris lumbricoides(Source: CDC)](\u002Fblogs\u002FAscaris-Eggs-1024x536.png)Figure: Various types of eggs of *Ascaris lumbricoides* (Source: CDC)\n\n- **Fertilized Eggs**: Fertilized eggs of *Ascaris lumbricoides* are broadly oval, with a thick, mammillated coat, usually bile stained a golden brown. These eggs measure up to 75 um long and 50 um wide.\n- **Unfertilized Eggs:** Unfertilized eggs of *Ascaris* are usually more oval, measure up to 90 um long, and may have a pronounced mammillated layer. Unfertilized eggs do not float (the eggs are too heavy) with the use of the zinc sulfate flotation concentration method.\n\n### Serodiagnosis\n\nAntibodies against *Ascaris* can be detected by the indirect hemagglutination method or by the [immunofluorescent antibody (IFA) test](\u002Findirect-fluorescent-antibody-ifa-test\u002F). These tests are useful for the diagnosis of extraintestinal ascariasis like Loeffler’s syndrome.\n\n## Treatment\n\n**Uncomplicated intestinal ascariasis** is treated with one of the following anthelmintics:\n\n- **Albendazole** — 400 mg single dose (most commonly used first-line agent)\n- **Mebendazole** — 100 mg twice daily for 3 days, or a single larger dose depending on regimen\n- **Ivermectin** — effective alternative\n- **Pyrantel pamoate** — preferred in pregnant women, since albendazole and mebendazole are generally avoided in pregnancy\n\nThese benzimidazole drugs work by blocking the worm's ability to absorb glucose, leading to glycogen depletion and reduced ATP production, ultimately killing the worm.\n\n**Intestinal obstruction:**\n\n- **Partial obstruction** is managed initially with intravenous hydration, nasogastric decompression, electrolyte correction, and antibiotics, alongside anthelmintic therapy. Resolution is typically defined by the return of bowel function (passage of stool\u002Fflatus), relief of colicky pain, and resolution of air-fluid levels on imaging.\n- **Complete obstruction** requires surgical intervention (laparotomy with worm mass removal and bowel repair) after initial resuscitation, since conservative management alone will not relieve a complete blockage.\n\n**Biliary or pancreatic ascariasis:** Endoscopic removal (ERCP with snare extraction of the worm) is often preferred over anthelmintic therapy alone when worms have migrated into the biliary or pancreatic ducts, partly because of the documented risk that single-dose albendazole treatment can prompt further worm migration into the biliary tree via the ampulla of Vater, as noted in the Mechanical Effects section above.\n\n**Re-treatment consideration:** Because reinfection is common in endemic areas due to ongoing environmental exposure, a repeat dose of anthelmintic 2–6 weeks after initial treatment is sometimes recommended, particularly following treatment of obstruction.\n\n## Where Students Actually Get Confused\n\n**1. \"Unfertilized Ascaris eggs are smaller and easier to find on concentration.\"** The opposite is true on both counts. Unfertilized eggs are actually **longer** (up to 90 μm vs up to 75 μm for fertilized eggs) — and critically, unfertilized eggs are **too heavy to float** using the zinc sulfate flotation concentration method, making them comparatively *harder* to detect with that particular technique. This is a frequently tested distinction: a patient harbouring only female worms may have a falsely reassuring flotation result despite genuinely passing eggs, since those eggs simply don't rise to the surface for collection.\n\n**2. \"Eggs found in stool are immediately infective to the next person who ingests them.\"** No — freshly passed eggs (fertilized or unfertilized) are not yet infective. As the life cycle section already states, fertilized eggs require approximately **2 weeks of development in warm, moist soil** before becoming infective. This incubation requirement is exactly why sanitation interventions that reduce the time between defecation and disposal\u002Ftreatment can interrupt transmission even without fully eliminating soil contamination.\n\n**3. \"Löffler's syndrome only happens with Ascaris.\"** The pulmonary larval migration phase responsible for Löffler's syndrome is not unique to *Ascaris* — hookworm larvae follow an essentially identical migratory pathway (skin or gut → bloodstream → right heart → pulmonary capillaries → alveoli → bronchial tree → swallowed) and can produce the same eosinophilic pneumonitis picture. A patient with unexplained cough, wheeze, and eosinophilia in an endemic area could have either organism as the cause — stool examination several weeks later, once the worms reach the intestine, is what eventually clarifies which.\n\n**4. \"A patient with an acute abdomen and a history of ascariasis just needs anthelmintic treatment.\"** For complete intestinal obstruction or confirmed biliary\u002Fpancreatic migration, anthelmintic therapy alone is not sufficient and may even be counterproductive in the biliary case (see Mechanical Effects above, on albendazole potentially worsening biliary migration). Surgical or endoscopic intervention is often required first, with anthelmintic treatment given afterward to clear the remaining intestinal worm burden and prevent recurrence.\n\n**5. \"Heavy worm burden always means severe symptoms.\"** Not necessarily — the article's own pathogenesis framework makes clear that even fairly substantial infections can remain asymptomatic in the intestine unless the burden is very heavy or the worms migrate somewhere problematic. Conversely, even moderate burdens can cause severe nutritional impairment in young children purely through chronic nutrient competition, without any acute mechanical event at all. Worm burden alone does not predict clinical severity — location and chronicity matter just as much.\n\n## Key Exam Facts in One Table\n\n| Fact | Detail | Memory hook |\n| --- | --- | --- |\n| Global burden | \\~1 billion cases annually | Most common human helminth infection |\n| Infective stage | Embryonated (fertilized) egg | Soil-transmitted — ingestion route |\n| Time for egg to become infective | \\~2 weeks in warm, moist soil | Freshly passed eggs are NOT yet infective |\n| Total cycle (ingestion to egg passage) | 8–12 weeks | Includes pulmonary migration phase |\n| Pulmonary migration duration | \\~10 days in the lungs | Same pathway as hookworm |\n| Fertilized egg size | Up to 75 μm long; thick mammillated coat, bile-stained golden brown | Smaller than unfertilized |\n| Unfertilized egg size | Up to 90 μm long; pronounced mammillated layer | Larger, but does NOT float in zinc sulfate flotation |\n| Zinc sulfate flotation limitation | Unfertilized eggs too heavy to float | Female-only infection may be under-detected by flotation alone |\n| Four pathogenesis mechanisms | Immune response, larval migration, mechanical effects, nutritional deficiency | Same organism, different presentation depending on timing\u002Flocation |\n| Löffler's syndrome | Eosinophilic pneumonitis from larval lung migration | Dyspnoea, cough, wheeze, transient eosinophilia |\n| Most serious mechanical complication | Intestinal obstruction (heavy worm burden) | Partial = medical management; complete = surgery |\n| Biliary\u002Fpancreatic migration risk | Worms enter via ampulla of Vater | Can cause cholangitis, pancreatitis, jaundice |\n| Treatment caution | Single-dose albendazole may worsen biliary migration | Endoscopic removal often preferred for biliary ascariasis |\n| First-line treatment (uncomplicated) | Albendazole (single dose) or mebendazole (3-day course) | Pyrantel pamoate preferred in pregnancy |\n| Nutritional impact | Malnutrition, stunting, vitamin A deficiency (night blindness), cognitive impairment | Most severe in children <5 years |\n| Serology use | Indirect haemagglutination or IFA | Specifically useful for extraintestinal disease (e.g., Löffler's) |\n\n## Self-Check Questions\n\n1. A stool sample from a woman with suspected ascariasis shows no eggs on zinc sulfate flotation, but direct wet mount of the sediment shows unfertilized eggs. What explains this discrepancy?\n2. A child plays in soil contaminated with freshly passed Ascaris eggs that day. Is the child at immediate risk of infection from that exposure?\n3. A patient presents with cough, wheeze, and peripheral eosinophilia. A colleague says this must be ascariasis since the patient has a history of passing roundworms previously. Why might this conclusion be premature?\n4. A patient with confirmed biliary ascariasis is treated with a single dose of albendazole. Two days later, symptoms worsen. What might explain this, and what alternative approach is often preferred?\n5. Using the four-mechanism pathogenesis framework described in this article, explain why a single organism can cause such different clinical presentations in different patients.\n6. Why is intestinal obstruction from Ascaris more commonly seen in children than adults, even though the same organism infects both?\n\n**Answers**\n\n1. *Unfertilized eggs are too heavy to float using the zinc sulfate flotation concentration method*, so flotation can give a falsely negative or reduced yield in a patient harbouring only female worms (and therefore only unfertilized eggs). Direct wet mount examination of the sediment, which does not rely on flotation, can still detect these heavier eggs.\n2. *Not from that specific exposure* — freshly passed Ascaris eggs are not yet infective. Fertilized eggs require approximately two weeks of development in warm, moist soil before becoming capable of causing infection. The child would be at risk from older, already-embryonated eggs present in the same soil, but not specifically from eggs passed that same day.\n3. *Löffler's syndrome (the pulmonary migration phase) is not unique to Ascaris* — hookworm larvae follow an essentially identical migratory pathway through the lungs and can produce the same eosinophilic pneumonitis picture. A prior history of passing adult roundworms confirms past intestinal ascariasis but does not rule out hookworm or reinfection with either organism as the cause of the current pulmonary presentation. Stool examination once any new infection reaches the intestinal phase would help clarify the cause.\n4. *Single-dose albendazole can paralyse worms in the intestine, which may prompt other worms to migrate toward the biliary tree through the ampulla of Vater*, potentially worsening biliary obstruction rather than resolving it. For this reason, endoscopic removal (ERCP with worm extraction) is often preferred over relying on anthelmintic therapy alone when biliary or pancreatic migration is suspected or confirmed.\n5. *The four mechanisms correspond to different stages and locations of the same organism's life cycle within the host*: host immune reactions to worm body fluids (ascaron) can occur at any time; larval migration through the lungs produces the allergic pulmonary picture (Löffler's syndrome) early in infection; mechanical effects depend on worm burden and location once adults are established in the intestine (or, problematically, elsewhere); and nutritional deficiency results from ongoing nutrient competition throughout the infection's duration. A patient's presentation reflects whichever process is dominant at the time they are examined.\n6. *Children are more likely to have heavier worm burdens* due to greater exposure (playing in contaminated soil) and repeated reinfection, and they have a proportionally smaller intestinal lumen diameter than adults — meaning a given mass of worms is more likely to cause complete obstruction in a child's narrower bowel than the same mass would in an adult's larger one.\n\n**References and further readings**\n\n- Sastry, A. S., & Bhat, S. (2014). *Essentials of Medical Parasitology*. Jaypee Brothers Medical Publishers (P) Ltd.\n- Garcia, L. S. (2016). *Diagnostic Medical Parasitology* (6th ed.). ASM Press.\n- Dold, C., & Holland, C. V. (2011). *Ascaris* and ascariasis. *Microbes and Infection*, 13(7), 632–637. \u003Chttps:\u002F\u002Fdoi.org\u002F10.1016\u002Fj.micinf.2010.09.012>\n- Khuroo, M. S., Rather, A. A., Khuroo, N. S., & Khuroo, M. S. (2016). Hepatobiliary and pancreatic ascariasis. *World Journal of Gastroenterology*, 22(33), 7507–7517. \u003Chttps:\u002F\u002Fdoi.org\u002F10.3748\u002Fwjg.v22.i33.7507>\n- Wongsaensook, A., Sukeepaisarnjaroen, W., & Sawanyawisuth, K. (2010). Biliary ascariasis after worm removal from the duodenum and single-dose albendazole treatment. *American Journal of Tropical Medicine and Hygiene*, 83(1), 22. \u003Chttps:\u002F\u002Fdoi.org\u002F10.4269\u002Fajtmh.2010.09-0793>\n- World Health Organization. (2023). *Soil-transmitted helminth infections*. WHO Fact Sheet. \u003Chttps:\u002F\u002Fwww.who.int\u002Fnews-room\u002Ffact-sheets\u002Fdetail\u002Fsoil-transmitted-helminth-infections>",[46,49,52,55],{"question":47,"answer":48},"Why does Ascaris lumbricoides cause such different symptoms in different patients?","Ascaris pathogenesis involves four distinct mechanisms tied to different stages and locations of the worm's life cycle: host immune reactions to worm body fluids (occurring at any time), larval migration through the lungs producing allergic pulmonary symptoms (Loffler's syndrome) early in infection, mechanical effects depending on adult worm burden and location in the intestine (or elsewhere if worms migrate), and chronic nutritional deficiency from ongoing nutrient competition. A patient's presentation reflects whichever mechanism is dominant when they are examined, which is why the same organism can cause anything from no symptoms to a surgical emergency.",{"question":50,"answer":51},"Why are unfertilized Ascaris eggs harder to detect using zinc sulfate flotation?","Unfertilized Ascaris eggs are too heavy to float using the zinc sulfate flotation concentration method, despite being larger (up to 90 micrometres) than fertilized eggs (up to 75 micrometres). A patient harbouring only female worms (and therefore only unfertilized eggs) may have a falsely reassuring flotation result. Direct wet mount examination of the stool sediment can still detect these heavier eggs even when flotation misses them.",{"question":53,"answer":54},"What complications can occur if Ascaris worms migrate to the biliary or pancreatic ducts?","Adult Ascaris worms can migrate from the small intestine into the bile duct or pancreatic duct via the ampulla of Vater, causing biliary colic, cholangitis, acute pancreatitis, or obstructive jaundice. Notably, a single dose of albendazole can paradoxically worsen this situation by paralysing intestinal worms in a way that may prompt other worms to migrate toward the biliary tree. Endoscopic removal via ERCP is often preferred over anthelmintic therapy alone when biliary or pancreatic migration is suspected.",{"question":56,"answer":57},"What is the treatment for Ascaris lumbricoides infection?","Uncomplicated intestinal ascariasis is treated with albendazole (single 400mg dose), mebendazole (100mg twice daily for 3 days), or ivermectin; pyrantel pamoate is preferred in pregnant women. Partial intestinal obstruction is managed with intravenous fluids, nasogastric decompression, and antibiotics alongside anthelmintic therapy, while complete obstruction requires surgical intervention. Biliary or pancreatic ascariasis is often managed with endoscopic worm removal rather than anthelmintic therapy alone.",[],[],[61,67,74,79,83,87,92,97,101,105],{"slug":62,"name":39,"description":63,"image":64,"body":65,"postCount":66},"acharya-tankeshwar","Editor-in-chief","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Ftankeshwar-acharya-author-microbeonline.jpg","***Tankeshwar Acharya, MSc (Medical Microbiology)***\n\n*Tankeshwar Acharya is an Assistant Professor in the Department of Microbiology at Patan Academy of Health Sciences (PAHS), Nepal, where he has been teaching and practicing clinical microbiology for over 14 years. He is the founder of Microbe Online, one of the leading free microbiology education resources on the web, covering bacteriology, mycology, parasitology, immunology, and clinical laboratory diagnostics written from direct experience in both the classroom and the diagnostic laboratory.*",433,{"slug":68,"name":69,"description":70,"image":71,"body":72,"postCount":73},"ashma-shrestha","Ashma Shrestha","SEO Copywriter and Science Communicator\nKathmandu, Nepal","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Fashma-shrestha.png","Ashma Shrestha holds a Master of Science in Medical Microbiology from the Institute of Science and Technology (IOST), Tribhuvan University, Nepal, where she developed a strong foundation in virology, molecular biology, and diagnostic microbiology.\n\nShe now works as an SEO Copywriter at Resolution Digital, where she combines her scientific training with research-driven content strategy. She is certified in Google Analytics and Google Business Profile (GBP), and brings a data-informed approach to science communication writing content that is not only accurate but structured to reach and serve the students who need it most.\n\nAt microbeonline, Ashma contributes articles primarily in virology and molecular biology, areas she finds most compelling for their mechanistic depth and their growing clinical relevance. Her writing reflects the same standard the site is built on: factual rigor, clear explanation of the *why* behind microbiology concepts, and content that helps students move from memorization to genuine understanding.\n\nShe is passionate about making complex microbiological concepts accessible without sacrificing accuracy; a skill that sits at the intersection of her scientific training and her professional work in content and SEO.",81,{"slug":75,"name":76,"description":77,"image":38,"body":38,"postCount":78},"sushmita-baniya","Sushmita Baniya","Author \u002F Contributor",32,{"slug":80,"name":81,"description":77,"image":38,"body":38,"postCount":82},"samikshya-acharya","Samikshya Acharya",20,{"slug":84,"name":85,"description":77,"image":38,"body":38,"postCount":86},"alisha-tripathi","Alisha Tripathi",6,{"slug":88,"name":89,"description":90,"image":38,"body":38,"postCount":91},"aastha-shrestha","Aastha Shrestha"," Author \u002F Contributor",10,{"slug":93,"name":94,"description":95,"image":38,"body":38,"postCount":96},"guest-author","Guest Author","Guest Author \u002F Contributor",2,{"slug":98,"name":99,"description":77,"image":38,"body":38,"postCount":100},"srijana-khanal","Srijana Khanal",18,{"slug":102,"name":103,"description":95,"image":38,"body":38,"postCount":104},"dr-poonam-acharya","Dr. Poonam Acharya",1,{"slug":106,"name":107,"description":77,"image":38,"body":108,"postCount":109},"nisha-rijal","Nisha Rijal","**Nisha Rijal** is a microbiologist and quality assurance specialist. She served for nearly 12 years as a microbiologist at the National Public Health Laboratory (NPHL), Nepal's national reference laboratory, and continues to work as a consultant microbiologist in international public health organization. ",51]