Card Set Information

2013-11-12 14:55:05

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  1. Ascaris lumbricoides - Round Worm
    Trichuris trichura - Whip Worm

    • Tropics and poor sanitation areas/ worldwide
    • transmission food & soil
  2. Ascaris lumbricoides - Round Worm

    Life Cycle
    • Live in Lumen of Small Intestine
    • Fertile eggs swallowed
    • Larvae hatch invade intestinal mucosa and migrate to lungs.
    • Larvae mature in lungs.
    • Adults develop in small intestine
  3. Ascaris lumbricoides - Round Worm

    Organism & Diagnosis
    • Find egg or worm in stool
    • OVA
    • Fertilized (corticated)- ovoid, 50-75, thick inner and outer shell.
    • Unfertilized: larger 50-90 μm elongated with thinner shell.
    • Decorticated: Occur in old specimens & outer shell is absent.
    • Worm:female 20-35cm & male 15-25cm
  4. Trichuris trichura - Whip worm

    Life Cycle:
    • Embryonated soil in swallowed
    • eggs hatch in small intestin and release larvae
    • Larvae mature to adults in the colon
    • Adults live in cecum & ascending colon
    • Unembryonated eggs are passed in stool
  5. Trichuris trichura - Whip worm

    *may see stunted growth

    Organsim & Dx
    • Organism:
    • worm 3-5cm
    • Ova: 50-23 μm with refractive plug at each end & thick double wall

    Dx: Microscopic exam of eggs in feces
  6. Enterobius vermicularis - Pin Worm

    • Worldwide
    • Young school aged children

    • Most common helminthic inf. in US
  7. Enterobius vermicularis - Pin Worm

    Life Cycle
    • Eggs are depositied on perianal folds from adult female
    • Eggs to mouth
    • Larvae hatch in small intestine & adults move to colon.
  8. Enterobius vermicularis - Pin Worm

    Clinical Disease
    anal itiching, appendicitis or asymptomatc
  9. Enterobius vermicularis - Pin Worm

    Organism & Diagnosis
    Worm: anterior ends have lips, esophagus ends in a bulb.

    Ova: 50-20 μm, ovoid with one end flattened

    Eggs from scotch tape prep
  10. Trichinella spiralis

    • Worldwide
    • carnivorous and omnivorous animals
  11. Trichinella spiralis

    Life Cycle:
    • Pigs ingest cnccyted larvae in uncooked garbage of sources form meat.
    • Man eats under-cooked pork 
    • Larvae mature to adult in intestine
    • Adults produce larvae in intestine
    • Larvae is carried via blood stream to muscle or organs ⇨ encyst
  12. Trichinella spiralis

    Clinical disease and Diagnosis
    Fever, muscle pain, edema around eyes, eosinophilia, splinter hemorrhages beneath finger nails. Neuroloigcal possible. 

    Dx: Muscle biopsy to identify larvae
  13. Hookworm

    Types, Host, & Location/Epidemiology
    • Human Host:
    • Necator americanus - Only found in US but most in S. America, africa, Sahara, & India
    • Ancylostoma duodenale - Europe, Mediterranean, S.America, India, & China

    • Cats & Dogs Host:
    • A. brazeliensis and A. caninum
  14. Hook worm

    Clinical Disease for:
    N. americanus - New World
    A. duodenale - Old World
    • Gournd itch (wherever the worm enters host)
    • ⇧ Not present in A. duodenale.

    diarrhea, abd pain, nausea, iron def.
  15. Hookworm

    Diagnosis/ distinction
    • Ova: Not differentiated from one another.
    • 40-70μm
    • Shell is thin and transparent with 2-8 cell masses inside

    • Worm: 
    • A. duodenale: 2 pair of Ventral teeth
    • N. americanus: sharp dorsal hook, cutting plate, barbed tip
  16. Hookworm filariform larvae
    • Infective Stage
    • Buccal cavity long
    • Esophagus extends 1/4 of the body lenght
    • Tail is pointed
    • Not seen in fresh stool
    • Matures in enviroment
  17. Strongyloides stercoralis

    Clinical Disease
    Tropical areas

    GI, Abd pain, diarrhea, pneumonia, eosinohilia
  18. Strongyloides stercoralis

    Life Cycle
    ~ Similar to that of hookworm
    • Free living form cycle or an intestinal cycle.
    • filariform larvae penetrate skin
    • filariform enter circulatory system & transported to lungs.
    • coughed up and swallowed back into small intestine to become adults.
    • Adult deposits egss in intestinal mucosa, hatch and migrate to lumen to recycle or become rabditiform larvae & get excreted.
    • cycle through again
  19. Strongyloides stercoralis

    Microscopic ident of larvae in stool or duodenal fluid.

    Most common with larvae found in stool
  20. Filaria
    Filariasis is caused by nematodes that inhabit the lymphatics and subcutaneous tissue of host.
  21. Filaria

    W. bancrofti & B. malayi
    • W. bandcrofti: Tropical areas worldwide 
    • B. malayi: islands of Indonesia & Asia


  22. Filaria

    Loa loa

    Fly Bite

    Noticed when worms migrate across eye

    loca pain, itching edama
  23. Filaria

    Onchocerca volvulus
    River Blindness

    Black Fly

  24. Filaria

    Life Cycle
    • Mosquito or fly bite host
    • larvae migrate to appropriate site & develop into microfilariae  producing adults.
    • Adults dwell in tissue for years & produce microfilariae which circulate in blood. Infecting arthropod that bites host
    • Except:
    • O. volvulus = circulates in eye or skin
    • M. streptocerca = skin
  25. Filaria

    Microscopic exam of usually microfilaria from blood &/or skin snips 

    Microfilaria 100-300μm in length & with or without sheaths, & nuclei in tail or not

    • worms (adult filaria) possible from tissue samples.
    • 2-50 cm
  26. Dracunculus medinensis - guinea Worm

    Location & clinical Disease
    • Narrow belt of African Countries
    • Walking Stick
    • Worm emerges from open ulcer

    Progressive extraction of worm over a period of several days.