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Nematodes, Cestodes , Trematodes

Nematodes, Cestodes , Trematodes. Slackers Facts by Mike Ori. Disclaimer. The information represents my understanding only so errors and omissions are probably rampant. It has not been vetted or reviewed by faculty. The source is our class notes.

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Nematodes, Cestodes , Trematodes

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  1. Nematodes, Cestodes, Trematodes Slackers Facts by Mike Ori

  2. Disclaimer The information represents my understanding only so errors and omissions are probably rampant. It has not been vetted or reviewed by faculty. The source is our class notes. The document can mostly be used forward and backward. I tried to mark questionable stuff with (?). If you want it to look pretty, steal some crayons and go to town. Finally… If you’re a gunner, buck up and do your own work.

  3. Describe a nematode

  4. Round spindle shaped worms that range in size from 1mm to 70cm. They undergo multiple larval stages. They are dioecious (separate sexes)

  5. What are the three methods of nematode infection

  6. Ingestion of eggs Ingestion of larva Direct penetration of skin

  7. Describe the relative frequency of nematode disease in children v adults

  8. Children > adults

  9. What are the intestinal nematoed and what are their common names

  10. Enterobiusvermicularis – pinworm Trichuristrichura – whipworm Ascarislumbricoides – roundworm Necatoramericanus – hookworm Ancylostomaduodenale – hookworm Strongyloidesstercoralis – none

  11. What is the life cycle of Enterobiusvermicularis

  12. Ingested eggs hatch in small intestine Adults live in colon Eggs deposits in perianal region nightly by females

  13. How is Enterobiusvermicularis diagnosed

  14. Sticky side out Scotch tape wrapped slide is pressed against perianal region. Tape is examined under microscope to identify the presence of eggs

  15. What is the hallmark clinical sx for Enterobius?

  16. Perianalpruritis

  17. What is the lifecycle of Trichuristrichuria?

  18. Ingestion of embryonated eggs from contaminated dirt. Larva hatch in small intestine Adults mature in colon where they burrow into the surface Eggs are passed in the feces Egg embryonate in the soil over 2-4 weeks

  19. What are the clinical sx of Trichuris

  20. None if worm burden is low. Otherwise tenesmus with chronic mucoid diarrhea occurs. Rectal prolapse may occur

  21. Why does rectal prolapse occur with Trichuris?

  22. The adult worms burrow into the epithelium and weaken it.

  23. Trichuris DX?

  24. O and P for O

  25. What is the lifecycle for Ascarislumbricoides?

  26. Ingestion of embryonated eggs which hatch in intestines Larva migrate to alveoli L3 larva break through into the alveolar spaces Larva migrate up trachea and are swallowed Adults mature in small intestines Eggs pass in feces Embryonate in soil for 2-4 weeks

  27. What is the relative size of ascaris?

  28. They can range up to 70cm

  29. Correlate the intensity of disease to Ascarischracteristics

  30. Disease intensity is dictated by worm burden. Higher burden results in greater likelihood of clinical sx.

  31. Relate eosinophilia to Ascaris infection

  32. Elevated when the worms are migrating to and especially when they are molting within the alveoli.

  33. How does Ascaris cause disease in the intestines

  34. Primarily through blockage

  35. Describe Necatoramericanus lifecycle

  36. Eggs hatch in the soil and larvate L3 larva directly penetrate the skin Larva migrate to the lungs and pass through to the alveolar space They are regurgitated and swallowed Adults mature in the small intestines Eggs pass in the feces

  37. How dowNecator and Ancylostoma vary in their paths of infection?

  38. Ancylostoma infection can also occur by direct ingestion of eggs in a manner akin to Ascaris. Wakana’s disease relates to ancylostoma infection by ingestion

  39. Describe the clinical disease

  40. Asthma from migration that is less sever than ascaris because molting does not occur. Anemia related adult repositioning every few days in the intestine coupled with anti-coagulant

  41. What is the dx for Necator and Acylostoma

  42. Direct microscopic observation of eggs passed in feces

  43. What is Strongyloides lifecycle

  44. L3 larva penetrate skin Larva migrate to lungs and break out of alveoli Larva migrate up trachea and are swallowed Adults mature in the small intestines Eggs ebryonate and hatch in the host L2 larva pass in feces L3 larva reinfect host

  45. How does Strongyloides infection differ from that of other intestinal worms?

  46. Strongyloides eggs hatch within the host resulting in the potential for autoinfection.

  47. Describe Strongyloides disease

  48. Pneomonitis Moderate to severe watery, moucousy diarrhea 10-40% eosinophilia

  49. Strongyloides

  50. What dictates the level of eosinphilia between Ascaris, Necator, Ancylostoma, and Strongyloides

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