Classes

• Two types of classes in Nematodes

  • Rhabditea
  • Enoplea
• Rhabditea - they are both free-living and parasitic forms. (Trichinella, Trichiuris)
• Enoplea - mostly free living, but includes some parasites. (Ascaris, Strongyloides, Ancylostoma, Wuchereria, Necator)
• Many nematodes are very important pathogens of humans and domestic animals
• Trichina worm - They infect humans, hogs, rats, cats, and dogs. Hogs can become infected by eating uncooked scraps of infected meat or rats
• Trichinella - cause trichinosis
• Trichinella – Larvae in cysts in Muscle
• Trichinosis

  • cysts within the muscles are consumed (undercooked food)
  • worm grows in intestine
  • forms cysts in the muscles of the new host
• 8 species of filarial nematodes that infect humans
• people in tropical countries are infected with Wuchereria bancrofti or Brugia malayi, which live in the lymphatic system.
• Filarial worms cause inflammation and blockage of the lymphatics
• The main vector of filarial worms is mosquitoes
• Filarial worms cause three main diseases:

  • Elephantiasis
  • River blindness
  • Dog heartworm
• Ascarid Worms lives in intestine
• Ascarid Worms eggs are passed out in the feces
• Hookworms are so named because the anterior (head) end curves dorsally, resembling a hook
• Hookworms have large plates in their mouths that cut into the intestines so that they can suck on the host’s blood
• Pinworm adults live in the large intestine and cecum
• Females pinworms migrate to the anal region at night and lay eggs, causing itching
• The scotch tape method consists of placing the sticky side of cellulose tape onto the anus overnight
• Eggs develop rapidly and become infective within six hours at body temperature
• When swallowed, these eggs hatch in the anterior end of the small intestine (the duodenum) and mature in the large intestine
• Trichuris trichuria - whip worm
• Ascaris lumbricoides - human giant round worm
• Ancylostoma duodenale - dog hookworm
• Enterobius vermincularis - pinworm