Heartworm is a parasitic roundworm that is spread from host to host through the bites of mosquitoes. When a dog is bitten by an infected mosquito, the transmitted larvae mature into adult heartworms. They then begin reproducing in the heart, lungs and surrounding blood vessels.

Heartworm disease is treatable if diagnosis is made and treatment is started early enough, but it can be fatal if ignored. It is also highly preventable. Orange County Animal Services recommends proactive care through heartworm preventative medication.

Common Misconceptions

• Misconception: Dogs can give heartworms to their owners.
  • Reality: People cannot get heartworms from their dogs. It’s a species-specific parasite that affects only dogs and occasionally cats.
• Misconception: Heartworm is contagious from one dog directly to another.
• Reality: Dogs cannot transmit heartworms to each other directly. Only a bite from an infected mosquito can transmit the disease.
• Misconception: Heartworm is inevitable.
  • Reality: Heartworm disease can be avoided by treating your dog with heartworm preventatives either topically, by pill or via injections.
• Misconception: Once a dog has been treated for heartworm, he or she can’t get heartworm ever again.
  • Reality: A dog can get heartworm disease even after he or she has been successfully treated and cured. That’s why prevention is so crucial.

In order to become a sponsor, please email HeartwormProgram@ocfl.net. A sponsor pledges $350 per dog, which is the cost of heartworm treatment. Many businesses choose to sponsor one animal per month, but any contributions are welcomed.

As a token of appreciation for their life-saving support, each sponsor’s logo will be displayed on OCAS’s website. They will also receive frequent recognition via social media. Not to mention, infinite gratitude from the shelter staff and animals alike.

Orange County Animal Services proudly partners with Pet Alliance of Greater Orlando to provide Heartworm Treatment to our sponsored Heartworm positive dogs. Once a heartworm positive dog is adopted, adopters can contact Pet Alliance of Greater Orlando to take the next steps to start heartworm treatment.

1. Is your dog already spayed/neutered?
1. Yes.
1. Proceed to step 2.
2. No.
1. Please refer to provided medical paperwork – it should indicate when to schedule an appointment with the Orange County Animal Services Clinic (prior to initiating Heartworm treatment). If it does not or you’re not sure, please call 407-254-9158 and have your animal ID ready.
2. Lost the medical paperwork? Call 407-254-9158 (Clinic Front Desk) and have your animal ID ready.


2. Contact Pet Alliance of Greater Orlando to schedule a consultation.
3. Once directed by Pet Alliance of Greater Orlando, start the 30 day doxycycline.
4. Day Zero- Begin heartworm preventive medication & 30 day doxycycline
5. Day 60 – Receive first treatment
6. Day 90 – Receive second treatment
7. Day 91 – Receive third (final) treatment
8. Day 120 – See the veterinarian (Pet Alliance) for a follow up visit
9. Day 270 (6 months after third injection) – Check up to see if Heartworm negative
10. Continue Heartworm preventative treatment for the lifetime of your dog

- If your dog left Orange County Animal Services with Upper Respiratory Infection proceed to use provided 10-day doxycycline as directed for 10 days after pickup.

- DO NOT start the 30 day doxycycline until directed by Pet Alliance of Greater Orlando to begin.