What is roundworm?

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Last updated: June 17, 2025View editorial policy

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From the Guidelines

Roundworm is a parasitic infection caused by Ascaris lumbricoides, typically transmitted through the faeco-oral route, and can be treated with a single dose of albendazole 400 mg or mebendazole 500 mg, or ivermectin 200 μg/kg, as recommended by the most recent guidelines 1.

Key Characteristics of Roundworm Infection

  • The prepatent period of roundworm infection is 2-3 months, during which the parasite develops within the host before symptoms appear or eggs are shed in the stool 1.
  • Roundworms are distributed worldwide, with the highest prevalence in rural areas of Africa, Asia, and South America, and are rare or absent in Europe, North America, and Australasia 1.
  • The mode of transmission is primarily through the faeco-oral route, where eggs from contaminated soil, water, or food are ingested, leading to infection 1.

Clinical Presentation and Diagnosis

  • Clinical presentation can range from asymptomatic to severe, with symptoms including abdominal pain, diarrhea, and occasionally gastrointestinal obstruction in children and biliary obstruction in adults 1.
  • Diagnosis is typically made through concentrated stool microscopy or faecal PCR to detect the presence of eggs or the parasite itself 1.

Treatment and Prevention

  • Treatment with albendazole 400 mg, mebendazole 500 mg, or ivermectin 200 μg/kg as a single dose is recommended for roundworm infection, as per the latest guidelines 1.
  • Prevention measures include proper handwashing, avoiding the consumption of unwashed fruits and vegetables, and improving sanitation practices to reduce the risk of transmission 1.

From the FDA Drug Label

Mebendazole tablets are indicated for the treatment of ... Ascaris lumbricoides (common roundworm)...

  • Roundworm refers to Ascaris lumbricoides, a type of parasitic worm.
  • It is also known as common roundworm.
  • The drug mebendazole is used to treat infections caused by this parasite 2.

From the Research

Definition of Roundworm

  • Roundworm, also known as Ascaris lumbricoides, is a type of nematode that infects the gastrointestinal tract of humans 3.
  • It is a common infection, particularly in tropical and subtropical areas, and is associated with substantial morbidity 3.

Causes and Transmission

  • Infection is initiated by ingestion of infective eggs, which hatch in the intestine 3.
  • The larvae then penetrate the gut mucosa and migrate through the liver and lungs before returning to the lumen of the small intestine, where adult worms dwell 3.

Symptoms and Complications

  • The usual presentation of roundworm infection is intestinal obstruction 4, 5, 6.
  • Rare but fatal complications include bleeding, perforation, and gangrene 4.
  • Intestinal obstruction is fatal in 6 per 100,000 children 5.

Treatment and Prevention

  • Effective chemotherapy is available, but long-term cure and ultimate eradication of the parasite require improved sanitation and changes in cultural habits 5.
  • Anthelmintic drugs such as albendazole, mebendazole, and ivermectin are effective against Ascaris lumbricoides infection, yielding high parasitological cure and large reductions in eggs excreted 7.
  • Prevention strategies rely on periodic mass drug administration to at-risk populations and improvements in water, sanitation, and hygiene 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Whipworm and roundworm infections.

Nature reviews. Disease primers, 2020

Research

The roundworm, Ascaris lumbricoides.

Primary care, 1991

Research

Anthelmintic drugs for treating ascariasis.

The Cochrane database of systematic reviews, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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