Pet Care 101: Heart Worm

Dirofilaria Immitis, commonly known as heart worm, is a nasty parasite that can cause some serious damage to your pets health!

How is it spread?

Heart worm is spread when a mosquito bites an infected dog and ingests the microfilaria (baby heart worms). The microfilaria then develop into little larva which are injected into the next dog (or cat/ferret) when the mosquito feeds again.

These little larvae are circulated all over the body in the blood vessels, and eventually mature into adult worms in the heart or lungs. The adult worms begin to reproduce more microfilaria which can then go on to infect more animals. This whole process takes around 6 months.

Why is it bad?

Adult worms can lodge in the vessels of the heart causing fatal blockages.

The adult worms lodged in the lungs cause a severe inflammatory reaction which can lead to narrowing of the airways and blood vessels of the lungs. They also grow in the heart which can eventually cause fatal blockages of the major blood vessels.

The symptoms of heart worm reflect this, with a reduced exercise tolerance, weakness and severe cough being the most common symptoms. Some animals will also lose weight and begin to have signs of poor health such as a dull coat.

How can we prevent it?

There are many options for heart worm preventions including daily tablets, monthly tablets, monthly spot on treatments and an annual injection. I personally like the Proheart annual injection because it can be given with your dogs vaccinations and ensures you will not forget. I know how forgetful I can be with monthly tasks!

If my dog gets heart worm can it be treated?

There is treatment available for dogs, it usually involves injections at the vet clinic with close monitoring. As the adult worms are killed there is some risk that they can dislodge and cause fatal blood vessel blockages, and even the dead worms can cause inflammatory reactions. Ultimately prevention is much easier than the cure!!! In very severe cases the worms may even need to be removed from the heart surgically.

How do I know if my dog has heart worm?

A simple blood test can be performed at the clinic with only a few drops of blood, and results are obtained in minutes! If your dog has not been receiving preventative treatment it is important to test them for heart worm first to ensure you wont kill any adult worms with the treatment, and to prevent them self infecting further.