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🦠microbiology review

Enterobius vermicularis

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Enterobius vermicularis, commonly known as the pinworm or threadworm, is a parasitic nematode that infects the human gastrointestinal tract. It is one of the most common helminthic infections worldwide, particularly affecting children and causing the condition known as enterobiasis or oxyuriasis.

5 Must Know Facts For Your Next Test

  1. Enterobius vermicularis is a small, white, thread-like worm that primarily infects the human colon and rectum.
  2. The life cycle of Enterobius vermicularis involves the ingestion of eggs, which hatch in the small intestine and migrate to the colon, where the adult worms reside and lay their eggs around the anus.
  3. Enterobiasis, the infection caused by Enterobius vermicularis, is the most common helminthic infection in developed countries, with a prevalence of up to 50% in some populations.
  4. The main symptom of enterobiasis is intense perianal itching, which is caused by the female worms laying their eggs around the anus.
  5. Enterobiasis is typically treated with anthelmintic medications, such as albendazole or mebendazole, which are effective in eliminating the infection.

Review Questions

  • Describe the life cycle of Enterobius vermicularis and explain how it contributes to the transmission and persistence of this parasitic infection.
    • The life cycle of Enterobius vermicularis begins with the ingestion of the microscopic eggs, which can be present on contaminated food, surfaces, or hands. Once ingested, the eggs hatch in the small intestine, and the larvae migrate to the colon, where they mature into adult worms. The adult female worms then migrate to the perianal region and lay their eggs around the anus, causing intense itching. The eggs can be easily transferred to others through direct contact or contaminated surfaces, leading to the rapid spread and persistence of the infection, especially in crowded living conditions or among young children.
  • Discuss the key clinical features of enterobiasis and explain how the symptoms can impact the quality of life for those affected.
    • The primary symptom of enterobiasis is intense perianal itching, which is caused by the female worms laying their eggs around the anus. This itching can be severe and disruptive, leading to sleep disturbances, irritability, and even secondary skin infections due to excessive scratching. The itching is often worse at night, when the female worms are most active in laying their eggs. The constant discomfort and disruption to sleep and daily activities can significantly impact the quality of life for those affected, particularly in children, who may experience difficulties in school and social settings due to the symptoms.
  • Evaluate the effectiveness of the standard treatment approach for enterobiasis and discuss any potential challenges or limitations in the management of this parasitic infection.
    • The standard treatment for enterobiasis involves the use of anthelmintic medications, such as albendazole or mebendazole, which are generally effective in eliminating the Enterobius vermicularis infection. However, one of the challenges in the management of enterobiasis is the potential for reinfection, as the eggs can be easily transmitted to others through contact or contaminated surfaces. Additionally, some individuals may experience recurrent infections due to incomplete eradication of the worms or the ingestion of new eggs. Furthermore, the widespread use of these medications can lead to the development of drug resistance, making the treatment of enterobiasis more challenging in the future. Comprehensive approaches, including education, improved hygiene practices, and community-based interventions, may be necessary to effectively control and prevent the spread of this common parasitic infection.