Help! My Dog Has Heartworm

Published: July 23, 2018

Academy Animal Hospital Greenwood Franklin

Did you know heartworm disease is much more widespread than it used to be? It’s now in zones where veterinarians rarely used to see it, like the northwestern U.S. and desert southwest. Why is this dangerous disease on the move?

Experts believe it’s happening due to changes in the environment. Climate change, commercial irrigation, and new construction are encouraging overpopulation of mosquitoes, the source of heartworm. That’s right - 100% of heartworm disease is caused by the bites of infected mosquitoes.

This means both good news and bad news about heartworm: It’s very preventable, but difficult and costly to treat if your dog already has it. Here are some things to keep in mind.

It Won’t Spread to You or Other Pets

This is the first question many concerned dog owners ask after a new heartworm diagnosis. Don’t worry - heartworm is only transmitted through mosquitoes, so you and your other pets can’t catch it from an infected pup.

In very rare cases, heartworm has been diagnosed in humans, but through mosquito bites not pets. And heartworm can’t complete its life cycle in humans, so it usually just causes a treatable infection or lesion.

A Pool or Pond Could be the Culprit

Anyone with a heartworm-infected dog instantly wonders why it happened. Standing water is the most likely contributor, because it attracts mosquitoes.

Common sources include poorly-maintained pools, stagnant ponds, and water buildup within outdoor piles of trash and clutter. Mosquitoes love these sources of standing water, where they can gather and breed.

It Happened Months Ago

Heartworm disease isn’t immediately detectable. Your dog likely had it for months before the diagnosis.

After a bite from an infected mosquito, it takes about 7 to 8 months for the larvae to mature into adult heartworms inside your dog’s body. The worms prefer your dog’s heart, blood vessels, and lungs, where they will continue to reproduce.

Over the months, as the worms spread, your dog may become lethargic or have trouble breathing. It happens so gradually, many dog owners don’t notice until the symptoms become extreme. Other symptoms include coughing, unusual swelling, and passing out.

It’s not uncommon for a dog to have dozens, or even hundreds, of 12-inch worms in its system at the time of diagnosis. Adult heartworms can live 5 to 7 years, reproducing and spreading throughout the dog’s body.

Now What?

Brace yourself: Treating heartworm is difficult but doable. Your veterinarian will explain the treatment plan and set up some guidelines for what needs to happen in the coming weeks.

Here are the typical steps to treating heartworm:

  1. Get an official diagnosis from a veterinarian. There are other conditions that can mimic it, so diagnosing it properly is important.
  2. Restrict exercise. Although it might be difficult, you must restrict your pet’s exercise for the duration of the treatment - about 3 months. Exercise allows heartworms to spread through your dog’s body.
  3. Follow your vet’s plan for treatment. Heartworm is treated various ways depending on its severity and how your pet’s system has been affected.
  4. Test and re-test. Your vet will do a test about 6 months after treatment to confirm the absence of heartworms, and your pet will need additional tests for the rest of its life.
Dogs with heartworm can recover and have healthy and happy lives. But they can always get heartworm again, so prevention is extremely important.

For more information about heartworm treatment and prevention, connect with Academy Animal Hospital.