Enterobius and Trichuris

• Enterobius Vermicularis


  Pinworm/threadworm, enterobiasis, oxyuriasis or seat worm infection
• Metazoa


  Multicellular organisms
• Nematoda


  Phylum of roundworms
• Objectives


  • Classification
  • Morphology
  • Transmission
  • Clinical Presentation
  • Diagnosis
  • Treatment
• Morphology forms


  • Ova
  • Adults
  • Larva
• Adult (Male & Female)


  • Small cylindrical, pointed at both ends
  • Female measures 8 mm x 0.5 mm
  • Male measures 2 – 5 x 0.2 mm
  • Males are smaller than females
  • Females have long pointed tails
  • Males have curved posterior ends
• Eggs/Ova


  • Ovoid asymmetrically flat on one side
  • Measure 50 to 60 mm long by about 20 to 30 mm wide
  • Have semi-transparent (thin) shell
  • Shell made up of an outer albuminous layer, two chitinous layers, and an inner lipoidal membrane
  • Outer layer (albuminous) is sticky
• The infection is cosmopolitan/worldwide
• Common characteristics of infection

  • More common in temperate than in tropical countries
  • More common in affluent than in underdeveloped countries
  • More common in Caucasians than in Negroes in the USA
  • Commonest helminthic infection in the US (18 million cases at any given time)
  • An urban disease of children in crowded environments
• Transmission


  By ingestion of embryonated eggs through contaminated hands, food, water, clothing, and bedding
• Man is the only host for Enterobius vermicularis
• Life cycle of E. vermicularis

  1. Embryonated eggs ingested

  2. Larvae hatch in the duodenum

  3. Develop in jejunum and upper ilium

  4. Adult worms descend into lower ilium, cecum, and colon

  5. Gravid females migrate to perianal region and deposit eggs
• Symptoms


  • Mostly asymptomatic
  • Most common symptom is irritation
  • Itching results in insomnia and restlessness
  • Loss of appetite
  • Gastrointestinal symptoms may develop
• In females


  • Pruritis vulvae
  • Vulvovaginitis
  • Salpingitis
  • Pelvic granuloma
• Diagnosis


  • Finding eggs in the perianal area
  • Adults around the anus, in the vulva, and on surfaces of stools
  • Scotch tape method or Graham swab
• Treatment


  • Albendazole
  • Mebendazole
  • Two doses of Pyrental Pamoate/Combantrin
  • Alternatives: Ketax, Antepar
• The whole family should be treated to avoid reinfection
• Bedding and underclothing must be sanitized between the two treatment doses
• Personal cleanliness is the most effective way in prevention
• Trichuris Trichiura


  Whipworm
• Objectives for Trichuris Trichiura

  • Classification
  • Morphology
  • Transmission
  • Clinical Presentation
  • Diagnosis
  • Treatment
• Morphology forms for Trichuris Trichiura

  • Ova
  • Adults
  • Larva
• Adult (Male & Female) for Trichuris Trichiura


  • A grayish-white worm slightly pink
  • A slender anterior
  • A thicker posterior end
  • The female is 50 mm long
  • Male is smaller and has a coiled posterior end
• Eggs/Ova for Trichuris Trichiura

  • Unsegmented ovum
  • Mucoid plug
  • Brown and single shelled
  • Characteristic barrel shape
  • Mucoid terminal plugs at each end
• A tropical disease of children (5 to 15 yrs) with about 500-700 million cases worldwide
• Transmission for Trichuris Trichiura

  • Ingestion of embryonated eggs in soil
  • Oro-fecal through contaminated fingers
  • Contaminated food and water
• Life cycle of T. trichiura

  1. Ingestion of embryonated eggs

  2. Larva escapes shell in upper small intestine

  3. Penetrates villus

  4. Larvae pass to caecum and embed in mucosa

  5. Reach age for oviposition within 30 to 90 days
• Symptoms for Trichuris Trichiura

  • Determined largely by worm burden
  • Less than 10 worms are asymptomatic
  • Heavier infections characterized by chronic profuse mucus and bloody diarrhea
  • Infection may result in malnutrition, weight loss, anemia, and death
• Diagnosis for Trichuris Trichiura

  • Clinically by examination of rectum
  • Presence of eggs in feces
• Treatment for Trichuris Trichiura

  • Mebendazole
  • Albendazole
  • Improved hygiene and sanitary eating habits