FA Q4, Parasites, II

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FA Q4, Parasites, II
2013-04-21 11:39:59
FA Q4 Parasites II

FA Q4, Parasites, II
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  1. how do benzimidazoles work?
    bind to tubulin on parasite - they starve
  2. which drug has widest safety margin and can be given extralabelly up to 10x dose to treat hypobiosis?
  3. Which benzimidazole is teratogenic?

    When during gestation can it be given?

    Ok during 1st and 2nd trimester (not during 3rd)
  4. which benzimidazole should not be given at same time as drugs for flukes?
  5. which parasiticide has narrowest margin of safety?

    Used to Tx...?

    What class of drug is it?

    treats adults and larval stages

    Cholinergic inhibitor (blocks acetylecholine causing worm paralysis)
  6. what are other examplse of cholinergic inhibitors?
    What stages can these treat?
    • Morantel
    • Pyrantel

    Only adult stages
  7. what is MOA for macrocyclic lactones?
    enhances GABA in worms - paralysis
  8. what stages will avermectins treat?

    What will it NOT treat?
    • Adults
    • Arrested larva

    • Does NOT tx
    • Tapeworms
    • Trichuris
    • (minimal effect on nematodirus
  9. with mass treatment strategies, which groups are usually dewormed? 5
    • Before parturition
    • Young, 1-3mos old
    • F's pre-breeding
    • Specific risk (bots after 1st freeze)
    • Pasture Rotation
  10. In most herds 80% of parasites are concentrated in what percent of the animals?
    20% have most of the burden and show signs
  11. What is FAMACHA?
    What does it evaluate
    What parasite does it screen for?
    Who is Tx?
    • MM compared to color scale
    • Evaluates for anemia
    • Hemonchus
    • Tx most affected (1 best/5 is palest)
  12. FAMACHA needs to be checked every 2 weeks in affected herds.
    Why is this still a beneficial system even though labor costs are higher?
    • Less dewormer- Save $
    • Reduced production loss from disease
  13. What egg count is consistent with Tx for goats?

    Goats (all): <500epg 

    • Sheep: <1000
    • Lambs: <500
  14. What is a successful fecal egg count reduction test?
    • Samples from ~10 animals =
    • 90% reduction w/in 1 wk of Tx
  15. if reduction is not at least 90% what can you do to improve it? 4
    • Fast animals before Benzimidazoles
    • Drench 2-3x Benzimidazole
    • Tx then reTx w/different class (in a few days or same time)
    • Improve pasture management
  16. should you dose based on heaviest or leanest animal in the same age group?
    Dose each age group based on HEAVIEST in the group - do not underdose
  17. should you recommend staying with same dewormer or changing each year?
    rotating each year if possible
  18. based on grazing behavior, which species is at highest risk of L3 ingestion?
    • Sheep - graze close to ground
    • Cattle - intermediate
    • Goats - browsers/least at risk as long as tall plants available
  19. what effect does south american camelid species' defecation behavior have on their pasasite risk?
    Communal dung pile= less risk as long as adequate pasture space
  20. how does grazing behavior relate to strength of immunity?

    Who build better immunity?
    Sheep and Cattle= better immunity as adults since graze closer to ground-more in contact w/parasites

    Goats/Camelids do not dev'l as good of immunity
  21. what are the 4 cornerstones of management of GI parasitism?
    • ⇩Infective larvae #
    • ⇩Stocking rate
    • Feed separate from feces
    • Judicious use of anthelmintics