What You Should Know About Heartworm in Dogs

yellow lab puppy held in vet's arms

There are a lot of things you need to be aware of and help protect your dog from. Preventive measures like flea and tick control are some of them and along with that is heartworm prevention. Part of prevention is also knowing what to look for and what to do if you see symptoms. Here’s what you should know about heartworm in dogs:

What is Heartworm?

Heartworm is caused by a parasite that is transferred to dogs from mosquitos. Unfortunately, dogs also are a naturally good host for the heartworm, which does not bode well for the dog if heartworm is left untreated. Heartworm is a serious condition that should be prevented and, if contracted, should be treated immediately.

Left untreated, it can be fatal. Heartworms infest the right side of the dog’s heart and, as they grow and reproduce, they infest the arteries and lungs as well. Adult heartworms can be up to a foot long! If left untreated, heartworms can lead to lung disease, severe damage to your dog’s body, and heart failure.

What are the Symptoms of Heartworm in Dogs?

Symptoms of heartworm in dogs usually manifest within 6-8 months after the parasite is passed on to them. At first, the symptoms may be unnoticeable or may seem like other common illnesses. A dog with heartworm often develops heart murmurs and may start out by coughing softly after some physical exertion. Over time, the cough will get worse, the dog will tend to be lethargic, get fatigued easily, and may not even be able to run or play. They may also exhibit a decreased appetite and start losing weight.

As heartworm progresses, the symptoms get more noticeable, but often still mimic other illnesses. The dog may seem lethargic and depressed, they may vomit or cough up blood, they may have diarrhea, and they may also just exhibit a difficulty breathing in general. Even though the symptoms of heartworm may mimic those of other illnesses, the more advanced ones are still symptoms you should never ignore in your dog. So, once you start seeing any of them, it’s important to get to the vet.

As heartworm progresses, it may cause excess fluid to build up in the abdomen, which will give your dog a swollen belly. Large numbers of heartworms can also suddenly block blood flow and lead to heart failure. A sudden onset of difficulty breathing, pale gums, and dark or bloody urine means your dog needs help and you need to get to an emergency vet immediately.

How do You Treat Heartworm in Dogs?

The best treatment for heartworm in dogs is preventing it in the first place. However, should your dog become infected, there are treatments available. You should be testing your dog for heartworm every year anyway as part of their regular checkup. But, it’s also important to test your dog for heartworm before administering any kind of preventive medicine because giving a dog preventive medicine when the parasite is already present can cause serious issues!

Once a dog has been diagnosed with heartworms, it is important to restrict their activity and begin treatment immediately. If there is a secondary infection or disease, it will need to be treated so your dog’s condition is stable. If the dog’s other symptoms are not too severe, a veterinarian may administer an arsenic compound to kill the adult worms. If heartworm is severe and close to causing blockages, it may require surgery and other approaches to remove the blockages and then get rid of the parasite.

It is important to catch and treat this disease as early as possible. Dogs with mild cases of heartworm have a high success rate with treatment. The more serious the case of heartworm is the more damage it does to the dog’s body, which makes it harder to treat and also increases the risk of other complications later.

How do You Prevent Heartworm in Dogs?

Thankfully, preventing heartworm is relatively easy. Preventive measures can be administered year-round and are available as a pill, topical treatment, and injection. Some topical treatments are also available as a combination of flea, tick, and heartworm protection.

But, heartworm prevention only works if there is no parasite present and if heartworms are eliminated before they reach the adult stage. This makes testing your dog regularly and administering prevention on a consistent schedule even more important. This is why keeping up with preventive medications is one of the winter safety tips for dogs that also applies year-round.

Puppies are at the same risk of getting heartworm as adult dogs, so they should be started on a heartworm preventive as soon as the product allows. They should be on it before they reach 8 weeks of age. Dosage is also important, so puppies that will gain weight quickly may need a higher dosage in the span of just a few weeks as they grow.

Making your regular vet visits and puppy wellness checks can help you plan for these increases appropriately. Plus, your veterinarian can suggest the approach, dosage, and products that might be the best fit for you and your puppy.

In addition to year-round prevention, you should also be getting your dog tested for heartworm once a year. If you have a lapse in prevention, you will want to get your dog tested and then start prevention again as soon as possible. Because the preventive medication only works on younger heartworms, it’s important to test your dog and make sure they did not become infected during the lapse in prevention.

Heartworm in dogs is a condition with serious consequences. By being proactive about prevention, you can help protect your dog from this disease and keep your dog’s heart healthy. Being a pet parent has its scary moments, but regular vet visits and other preventive measures can go a long way in reducing risks and helping your dog stay happy and healthy!