My Dog Has Heartworms, Now What?

heartworm | prevent heartworms | heartworm medication



Heartworms are twelve-inch long worms that live in the heart of dogs.  They are transmitted from one infected dog to another by mosquitoes.  It is fifteen times more expensive to treat for heartworms than it is to prevent them, and missing one single dose of prevention can put your dog at risk to this deadly parasite.




The life cycle of heartworms:

Before we talk about heartworm treatment, it is necessary to understand the heartworm lifecycle.  A mosquito bites an infected dog and ingests microfilaria (baby heartworms).  Within the mosquito, the microfilaria develops into an infective stage.  The mosquito then bites another dog and injects the larvae under the pet’s skin.  For the next two months, the larvae continue to develop and migrate through the dog’s tissue.  This is the stage where heartworm prevention is effective.  Once the larvae reach the bloodstream, the prevention will no longer work, and treatment is required.  Within the next four to five months the larvae begin developing into adult worms.  Around six months, the heartworm has reached the heart and is a mature adult.

After a diagnosis of heartworms, it will be necessary for your veterinarian to perform bloodwork and chest x-rays.  This helps us determine what class of heartworm disease your dog has and if the heartworms have caused any complications.

Treatment of adult heartworms:

Day 1:

  • Administer heartworm prevention
  • Administer doxycycline, an antibiotic, which helps sterilize and shrink the adult heartworm.

Day 30:

  • Administer heartworm prevention

Day 60:

  • Administer heartworm prevention
  • Decrease activity level. Dogs must be confined to a cage and leash walked when outside.
  • 1st injection of Immiticide to kill the adult heartworm
  • Administer a steroid to help decrease any chance of complications from the dying heartworms.

Day 90:

  • Administer heartworm prevention
  • Continue with restricted activity for one more month
  • Administer 2nd injection of Immiticide
  • Administer steroids again

Day 91:

  • Administer 3rd injection of Immiticide

Day 120:

  • Administer product to kill microfilaria

Day 270:

  • Antigen heartworm test six months after completion

As you can see, it takes time to treat for adult heartworms.  Waiting until day sixty to begin adult heartworm treatment allows any immature heartworms to get into the heart so that they can be killed.  After treatment, it is necessary to keep your dog on heartworm prevention every 30 days all year around.  Yearly testing is also necessary.

During the month of April, you can enter into our contest to win a year’s supply of heartworm prevention with every purchase of heartworm prevention you purchase from Guthrie Pet Hospital.

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