NEMATODES-F

• Nematoda

  • Multicellular parasites that appear round in cross section
• Larvae

  • In the appropriate environment, developing __ located inside fertilized eggs emerge and continue to mature. These are typically long and slender.
• Pinworms

  ingestion of the infected eggs transmits the disease.
• Hookworm larvae

  burrow through the skin of the foot and make way into the intestinal tract.
• Serologic test methods

  are available for the diagnosis of select nematode organisms.
• factors may contribute to the ultimate severity of a nematode infection:

  1. The number of worms present;
  2. The length of time the infection persists;
  3. The overall health of the host
• Intestinal Species

  1. Enterobius vermicularis
  2. Ascaris lumbricoides
  3. Ancylostoma duodenale & Necator americanus
  4. Trichuris trichiura
• Instetinal-Tissue Species

  1. Trichinella spiralis
  2. Dracunculus medinesis
• Enterobius Vermicularis

  • commonly known as pinworm or seatworm
  • parasitic only to humans
• E. v. Adults inhabit the ileocecus, that is, cecum and adjacent ascending colon and distal ileum.
• The infection of E. Vermicularis may cause Enterobiasis
• Enterobius vermicularis egg Morphology:

  48-60 long 20-35 wide

  Oval, one side flattened

  may be enbryonated/unembryonated

  double-layered, thick
• Enterobius vermicularis adult Morphology:

  F7-14mm

  M2-4mm

  F/M yellowish white

  Fpointed; resembles pinhead
• Ascaris lumbricoides is a roundworm that can be found in the intestines of humans and other animals
• An A. lumbricoides egg morphology:

  unF 85-95um by 38-45um

  unbryonated

  thin

  usually corticated
• An A. lumbricoides egg morphology:

  F 40-75um by 30-50um

  rounder

  undeveloped unicellular embryo

  thick chitin

  corticated or decorticated
• Infectionof A. lumbricoides causes Ascariasis
• Trichuris trichiura

  • 800 million people infected worldwide
  • Children living in poverty in the tropics and subtropics
  • It is most common in poor rural communities and areas in which sanitary facilities are lacking
• Trichuriasis

  • Common symptoms found in infected persons include abdominal tenderness and pain, weight loss, weakness, and mucoid or bloody diarrhea.
• Mebendazole causes worm death by selectively and irreversibly blocking glucose uptake and other nutrients in the susceptible adult intestine where helminths dwell.
• Albendazole decreases,ATP production, causing energy depletion, immobilization, and death.
• Trichinella spiralis is a roundworm that is found in pork
• T. spiralis encysted larva morphology:

  75-120um

  coiled
• T. spiralis adult morphology:

  F/M Thin anterior end, small mouth, long slender digestive tract

  F blunt, round posterior end

  M curved posterior end
• for T. spirlis, other laboratory findings such as eosinophilia and leukocytosis may also

  serve as indicators for disease.
• Trichinosis

  • shows seasonal fluctuations, reaching its peak during the winter months when there Is greatest consumption of pork.
• Patients with severe infections (trichinosis) that may be potentially life-threatening are usually treated with prednisone.
• Dracunculus medinensis is a parasitic nematode that causes guinea worm disease
• Guinea Worm

  • a white worm emerging from a skin lesion.
  • Its length is between 60cm - 120 cm
  • Infection occurs when a person drinks contaminated water containing water fleas
• D. medinensis larva morphology:

  620 by 15um

  consumes 1/3 of body length
• D. medinensis adult morphology:

  F 840 by 1.5mm

  Prominent rounded anterior end

  M 21 by 0.4mm

  Anterior end coils itself
• Dracunculosis is a parasitic disease caused by the nematode Dracunculus medinensis