Symptoms of Heartworm Disease in Dogs

Heartworm disease is a life threatening and very frightening medical condition that can occur in both dogs and cats. Luckily, there are fairly reliable ways that you can prevent heartworm disease in your pet.

Most of the time very early stages of heartworm disease will exhibit no symptoms in dogs at all. However, as the disease progressives the symptoms will increase in severity as well. These symptoms can range from coughing to heart failure depending on how advanced the stage of heartworm disease is.

Here we will be explaining everything that there is to know about heartworm disease in dogs. This includes what heartworm disease is, how dogs can get it, and what the symptoms of heartworm disease in dogs are. In addition to this, we will also be explaining how you can prevent heartworm disease in dogs along with how it is diagnosed and treated by a vet. Let’s get into it.


What Are Heartworms?

Heartworm is an internal parasite that primarily lives in a dog’s cardiovascular system. This mainly includes the heart and blood vessels. Heartworms commonly infect a dog’s lungs as well because they are connected to major blood vessels.


How Can Dogs Get Heartworms?

Heartworm is passed to dogs through mosquitos. The mosquito does this by picking up heartworm larvae from an infected animal and then injecting the larvae into the next animal that they bite.

Heartworm disease is present throughout the globe, and it is increasing in prevalence as the years go by. However, the risk for the disease does increase in areas with many stray dogs and cats and in areas with a large mosquito population.

Symptoms of Heartworm Disease in Dogs in Buffalo Grove, IL

Symptoms of Heartworm in Dogs

Although early stages of heartworm disease in dogs do not tend to exhibit obvious symptoms, there are still symptoms of heartworm disease that dog owners should be aware of. Unfortunately, many of these symptoms only appear in advanced stages of a heartworm infection. Here are the symptoms of heartworm in dogs.


A mild cough is often one of the first symptoms of heartworm that are noticeable in dogs. In early stages of the disease this coughing is usually very mild, but it often worsens in severity as the heartworm infection progresses.


Lethargy is another symptom that some dog owners notice early on in dogs with a heartworm infection. Early on this lethargy is usually just after mild to moderate amounts of exercise. However, like coughing, this lethargy tends to increase in severity as heartworm disease progresses in dogs.

Reduced Appetite

Over time many dogs with heartworm disease will also develop a reduced appetite. This means that they will not eat as often as they normally would. This can show up early on in a heartworm infection. However, this symptom is more characteristic of a moderate heartworm infection in dogs.

Weight Loss

Over time this reduced appetite will often lead to weight loss in dogs. Weight loss is usually indicative of a more severe case of heartworm disease. This is especially true if the weight loss is severe.

Heart Failure

Unfortunately, very severe cases of heartworm disease in dogs will usually result in heart failure. This is because the worms have affected the heart so much that it can no longer function properly. Of course, if you suspect that your dog is experiencing heart failure then you should take them to the emergency vet immediately.

A Swollen Abdomen

A swollen abdomen is another sign that a dog has a very severe case of heartworm disease. This symptom occurs because the dog’s immune system creates a buildup of fluid around the lungs and abdomen in an attempt to fight off the heartworm. This symptom is often accompanied by extreme lethargy and difficulty breathing.

The Onset of Caval Syndrome

Caval syndrome occurs when the heartworms create a physical blockage within a dog’s heart. This blockage prevents blood from being pumped from the heart to other parts of the body. Signs of caval syndrome in dogs includes:

  • Labored breathing
  • Pale pink or white colored gums
  • Bloody or dark colored urine

Caval syndrome is a life-threatening condition in dogs that is considered to be a medical emergency. As a result, you should take your dog to the emergency vet immediately if you notice any of the above symptoms. At this stage of heartworm disease dogs will require emergency surgery in order to save their life.


How Can You Prevent Heartworms in Dogs?

Luckily, heartworm disease is a condition that is fairly preventable in dogs. There are numerous different brands of heartworm prevention medication out there. These medications are usually in the form of a pill that you will need to give dogs once a month.

Although you will need to pay for this heartworm prevention medication, it is well worth it knowing that your dog is protected from this potentially life threatening disease. Plus, it would save you money in the long run as treating heartworm infections in dogs can be quite expensive.

Heartworm Disease in Dogs

How Is a Heartworm Infection in Dogs Diagnosed?

Heartworm disease is diagnosed by a vet through a blood test. In this blood test the vet will look to see if they can find any heartworm larvae in the dog’s blood sample. If they do find heartworm larvae then the test will come back positive, and if they do not find any heartworm larvae then the test will be negative.

This is the same test that many vets will offer to dog owners when they take their dog to their annual vet exam. In these cases this is just a preventative precaution to ensure that your dog is heartworm free. Vets may also call for this test as a precaution if your dog has recently had a lapse in heartworm prevention medication.


How Is a Heartworm Infection in Dogs Treated?

In all heartworm cases vets will call for a decrease in physical activity. This will make your dog more comfortable throughout the treatment process. Most heartworm infections are treated through dewormer medication. However, in extreme cases emergency surgery may be necessary as well.


Here at Buffalo Grove Animal Hospital, we care about your pet and its health. Call us at (847) 394-1128 for any questions regarding heartworm disease and your dog’s health.

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About Buffalo Grove Animal Hospital

Buffalo Grove Animal Hospital has been a part of the Buffalo Grove community since 1969. Our veterinarians serve Buffalo Grove, Arlington Heights, Palatine, and the surrounding areas with the best veterinary medicine year after year. Our commitment to pet health runs deep, and we’ve proven our skill and compassion by becoming an AAHA-accredited Animal Hospital, the highest accreditation veterinary practices can receive.