Everything You Need To Know About Heartworm In Dogs
Causes, treatment, prevention and more ❤️

As a pet parent, you know heartworm disease isn’t something you want your dog to have.
But why, exactly? What can you do to keep your dog from getting heartworms? And what happens if your pup does end up diagnosed with a heartworm infection?
Don’t worry — The Dodo’s got you covered!
Consider this your go-to guide for everything you need to know about heartworm in dogs.
JUMP TO: How do dogs get heartworm? | Heartworm symptoms in dogs | Heartworm treatment for dogs | Heartworm preventions for dogs
What is heartworm in dogs?
Heartworm disease is a potentially fatal parasitic infection where worms live in your dog’s heart.
It’s an incredibly dangerous condition because the worms can cause major physical damage while in your pup’s pulmonary artery (aka the artery that carries blood from his heart to his lungs).
Heartworms can cause inflammation while they’re alive and even blockages when they die.
Your dog can also develop complications from his immune response to having heartworms in his system.
How do dogs get heartworms?
Dogs can only get heartworms from one source: infected mosquitos.
That can feel a little overwhelming, since mosquitos are practically everywhere. But dogs can’t get a heartworm infection from other dogs, luckily, and mosquitos are the only way a dog can get heartworms.
The way it works is a mosquito will pass heartworm larvae to your dog when biting him.
The larvae will then pass through your pup’s skin and travel to his heart.
Heartworm symptoms in dogs
One of the things that makes heartworm disease so scary is that most dogs won’t show any symptoms at all.
If your dog does show signs of heartworm disease, it can be tough to diagnose him from symptoms alone.
That’s because mild forms of heartworm disease can result in symptoms that are actually common across a bunch of other conditions, and any intense symptoms won’t show up until your dog’s illness has already gotten pretty serious.
Visible symptoms could include things like:
- Coughing
- Difficulty breathing
- Abdominal swelling
There are also some internal symptoms, meaning you can’t see them since they’re happening inside your pup’s body — which is why annual screenings for heartworm disease are so important.
Heartworm treatment for dogs
Heartworm treatment is a really intense process for dogs.
It involves a lot of steps —your pup will need several rounds of various medications, steroids, preventatives and hospitalization.
This means treatment will take a really long time, but it’s important to complete every single step.
Heartworm treatment for dogs is far from a painless process, and a big part of it includes keeping your dog inactive throughout treatment and recovery.
And it’s important that you follow your pup’s treatment protocol exactly to avoid any complications.
Is heartworm treatment painful for dogs?
Treating your dog’s heartworm can also be pretty painful for him because the medicine (aka melarsomine) he needs to kill the adult worms is really intense — mostly because it’s arsenic-based.
So, the medicine can cause some painful tissue irritation.
It also comes in the form of a fairly large injection, so your pup will probably feel sore afterwards since the needle itself can hurt his muscles.
Caring for a dog after heartworm treatment
Luckily, your dog has you to take care of him after his heartworm treatment.
Treatment aftercare means making sure he gets plenty of rest and relaxation since it’s crucial that your pup stays inactive for a while after his treatment.
If he exercises too much too soon, it could cause even more problems.
Heartworm prevention for dogs
The good news is heartworm disease is easily preventable.
There are a whole bunch of oral medications that protect your dog from getting heartworms, including some oral medications that even keep fleas and ticks away, too.
Or if you’d prefer, there are also injectable options.
Both oral and injectable heartworm preventatives work the same — by killing heartworms while they’re still larvae and before they can actually make it to your pup’s heart.
Your vet can help you decide the best heartworm prevention option for your pup.
But no matter which one you choose, make sure you stay on top of those preventatives so your pup won’t have to go through any of this.