Vet 218 Heartworms

  1. Scientific name of the heartworm.
    Dirofilaria Immitis
  2. How long can L1 remain in the bloodstream?
    Up to 2 years
  3. How long does it take for the L1 to develop into the infective L3 stage once ingested by the intermediate host?
    10-14 days/ 2-3 weeks
  4. What is the temp requirement for L1-L3 in the mosquito?
    70 degrees
  5. What is the lifespan of adult heartworms?
    5 years
  6. How long does it take for the L3-L4 molt?
    2-4 days
  7. How long does it take for the L4-L5 molt?
    50-70 days
  8. How long does it take for the L5 to mature to adult once they migrate to the pulmonary arteries and right heart?
    3-4 months
  9. What is the prepatent period for heartworms?
    6 months
  10. What are the 4 diagnostic lab tests for microfilaria?
    • Modified Knott's
    • Filter (ex Difil)
    • Buffy Coat
    • Direct Smear
  11. What are some ways of diagnosing heartworms other than testing for microfiliaria or anitgen/antibody tests?
    • Radiograph: enlarged pulmonary arteries and right heart
    • ECG
    • CBC: increased basophils/eosinophils
  12. What is occult heartworm disease?
    Presence of adults without microfilaria
  13. What are the five possible reasons for occult heartrworm disease?
    • Immature adults
    • Adults one sex or sterile
    • Ectopic adults
    • Immune mediated clearence
    • Montly prevetative: kill microfilaria
  14. What are two considerations before starting TX of heartworms?
    • Cost: can the client afford tx?
    • Overall health of animal: liver, kidney function, able to withstand tx.
  15. What tx is older and less effective (63%)?
    thiacetarsamide (Caparsolate)- given IV, bid, 2-3 days
  16. What tx is newly approved and more effective (90.8%)?
    melarsomine dihydrochloride (Immiticide)- deep IM sid/bid, 2 days
  17. What two products are used off label as microfilaricidals?
    • Ivermectin
    • Milbemycin oxime
  18. Ivermectin + Pyrantel pamoate (Heartgard 30 plus, Iverheart, TriHeart Plus)
    HW prevention, rounds, hooks
  19. Milbemycin oxime (Interceptor)
    HW prevention, rounds, hooks, whips
  20. Selamectin (Revolution)
    monthly topical; HW prevention, rounds, hooks in CATS ONLY, fleas, some mites, some ticks.
  21. Lifespan of adults in cats
    2 years (vs 5 years in dogs)
  22. Prepatent period in cats
    8 months (vs 6 months in dogs)
  23. Moxidectin (Proheart 6)
    SUBQ injection, every 6mo. HW preventative, hookworms @ time of admin.
  24. What are some HW preventatives in cats?
    • Ivermectin (Heartgard 30 for cats)
    • Selamectin (Revolution)- also rounds, hooks in cats
    • Advantage Multi
    • Interceptor
  25. What is meant by "caval syndrome?"
    Adults in the right heart and vena cava.
  26. What are some clincal signs of heartworm disease?
    • Exercise intolerance
    • Chronic cough
    • Dyspnea
    • RemittentĀ  ascities
Card Set
Vet 218 Heartworms