Heartworm and Your Pet

How many of us give our dog that monthly chew that does something with a worm and the heart and call it good? Well today, that is going to change. I want everyone to be well educated in one of the most significant diseases that can affect both our dogs and cats!

What is Heartworm?

Heartworm is a parasite that enters the blood stream as a larva (immature form of the worm) via a mosquito bite. In the animals’ body it then travels to the heart and lungs where it will become an adult worm. Here it will become sexually mature and produce microfilaria (immature form of the worm) which a mosquito then ingests and turns into a larva and restarts the cycle.

Why do we care about Heartworm?

As the adult worms grow in the heart they cause the heart chamber to grow as well. This eventually leads to heart failure due to the heart not being able function properly. The worms can also act as an embolus (similar to a clot) and this can cause damage to the lungs and other vital organs as they travel through the blood stream.

What are the symptoms of Heartworm?

The scary part of this disease is that at the initial stages of the disease there are no symptoms. It is not until the disease is advanced enough to cause heart failure or become emboli that you can diagnose the disease based on clinical symptoms such as coughing and lack of energy. This is why PREVENTION and regular TESTING is the best way to tackle this potentially life threatening disease!

What is heartworm testing?

The standard test is a screening test that looks for Antigen produced by the female worms. An antigen is a protein that the worms produce that go into the blood stream that we can test for. If this test is positive it means there is adult worms already present in the heart. You can also take a blood sample to look for the microfilaria (immature form of the worm) in the blood stream.

Microfilaria in Blood


What is the Prevention and treatment of Heartworm disease?

This is a true example of an ounce of prevention is worth a pound of cure! The medications that we use monthly kill the immature form of the worm before it can ever develop into an adult worm. Monthly medications like Heartgard© act retroactively. That means that any mosquito that bites and transfers the larva into the blood stream up to 30 days before the Heartgard© is given will be killed before it even has a chance to become an adult worm.

We do have medications that can treat adult worm if we miss this stage, however they are not only very expensive but carry significant risk. We use an injectable called Melarsomine that has to be given deep into the muscle in a series of 3 painful injections spread out by a month. There has already been potential damage to the heart and it increases the risk of allergic reactions and emboli that could be fatal to your pet. It is also significantly more expensive then the monthly prevention, you can protect your dog with Heartgard© for multiple years for the price of one heartworm adulticide treatment!

As always we strive to help keep your pets safe and would love to discuss heartworm and prevention with you! Call us now to schedule an appointment. We look forward to seeing you!