Skip to Content Skip to Content

Heartworm Treatment


What to Expect with Memphis Animal Services’ Heartworm Treatment


Heartworm disease is a serious, potentially fatal disease in pets in the United States and many other parts of the world.

What causes heartworm disease?
It is caused by foot-long worms (heartworms) that live in the heart, lungs and associated blood vessels of affected pets, causing severe lung disease, heart failure and damage to other organs in the body.  Heartworms are transmitted from one pet to another when a mosquito bites and takes a blood meal from one infected pet and then bites another pet. 

Is heartworm disease contagious?
Your other pets are NOT in danger of getting heartworm disease from your new dog as long as they are current on heartworm preventative as directed by your veterinarian.

What are the symptoms of heartworms?
In the early stages of the disease, many dogs show few symptoms or no symptoms at all. The longer the infection persists, the more likely symptoms will develop, such as:

  • Mild persistent cough
  • Reluctance to exercise
  • Fatigue after moderate activity
  • Decreased appetite
  • Weight loss


If untreated, heartworm disease will kill your dog. It causes lasting damage to the heart, lungs and arteries, and can affect the dog’s health and quality of life long after the parasites are gone. As it progresses, it can cause caval syndrome, which leads to heart failure and sudden blockages of blood flow, which few dogs survive without emergency surgery.


Heartworm treatment is included in your adoption fee!*

Thanks to grant funding from PetSmart Charities and Petco Foundation and support from individual donors, MAS is happy to be able to provide heartworm treatment for your pet, *provided that our veterinarian determines them a suitable candidate for our treatment protocol. Normally, heartworm treatment can cost anywhere from $500 to $1,500 at a private vet, depending on the size of the dog, the protocol used, and how advanced the disease is.


The ideal way to treat heartworms is at a private veterinarian where they can do a full workup and customize the treatment. You may choose to have your new dog’s heartworm treatment done at your own vet at your expense, and we completely understand that. You will most likely be able to complete treatment sooner if you choose this option, as MAS has a high volume of heartworm-positive dogs to provide treatment for. If you have a personal vet and you decide to get your dog treated for heartworms at MAS, be sure to let your vet know.

MAS will only provide heartworm treatment for dogs we consider candidates for our shelter protocol, typically dogs whose heartworm disease has not advanced to the point of showing symptoms; symptomatic dogs must be treated at a private vet at the adopter’s expense.


All of these times are approximate. The vet clinic will make your appointments with you, so you will know exact dates to come back for treatment.

STEP 1 You process the dog’s adoption. If the dog is not already spayed or neutered, he/she will stay with us and have surgery in the next several days. If he/she is already fixed, you can take your new family member home today!
When your pet is discharged, you will be given:
• A customized heartworm treatment schedule with your injection appointment dates
• Dose of Heartgard to be given at home
• 30 days of doxycycline to be given at home
• Prescription for 12 months of Heartgard 
STEP 2Begin preparing your home and your family for your dog’s exercise restriction. Get your pet used to kennel time and potty walks on leash.
STEP 3On your scheduled injection dates, you will drop your dog off at our vet clinic in the morning, two mornings in a row, to have their injection by a vet. He/she will be monitored for the day and you will pick him/her up each afternoon.
STEP 4FOR TWO MONTHS AFTER THE INJECTIONS, DO NOT ALLOW YOUR DOG TO RUN AROUND! This is the time when extremely restricted activity is required.
STEP 5Continue to administer the heartworm preventative we prescribed for you, or other heartworm preventative approved by your private veterinarian, as directed.
STEP 68 months after the injections, take your dog to your private veterinarian to be re-tested for heartworm disease. Keep your dog on heartworm preventative as directed by the vet for the rest of his life.


Heartworm disease, as well as the treatment of heartworm disease, can lead to serious risks and complications. You can reduce your dog’s risk of complications by doing the following:

You must restrict activity for your heartworm-positive dog until 8 weeks after your final injection. 

Dogs who are allowed to run, play, and get their heart rate up can cause the weakened heartworms to shatter abruptly, blocking off blood flow to the lungs, brain, or other organs. This causes a stroke or sudden death. When you restrict their exercise, the weakened heartworms die off more slowly which is safer for your dog.

We know it’s difficult to keep a young, active dog from running and playing. Here are some tips to avoid bursts of activity that can put your dog in danger:ONLY let your dog outside on a leash. For potty breaks, take your dog out on a leash and come right back in as soon as he’s done. Do not let him loose in a yard where he could run around.
Crate your dog or confine him to a single room when you’re not home.
Give your dog plenty of low-key enrichment activities that do not require walking around, such as eating his meals from a Kong or puzzle toy.


Restrict activity
You must not allow your dog to run or get his heart rate up until at least 8 weeks after his final injection.

Continue giving your dog heartworm prevention medicine
Fill the prescription we gave you (or use an alternate product as directed by your veterinarian). Continue to use heartworm preventative as directed and as scheduled by your veterinarian.

Re-test your dog in 8 months
It can take up to 8 months for your dog to be completely cleared of infection. Schedule an appointment at your personal veterinarian 8 months after your dog’s final injection to test for heartworms.

Once your dog has tested negative for heartworms, YAY! It’s time to celebrate! He can now run and play and romp all he wants!