Heartworm Prevention


Heartworm Prevention

Firstly, it is very important to understand there are two broad categories of worms that are different and may affect your pet dog and cat; heartworm and intestinal worms.

Heartworm (Dirafilaria immitis) is a parasite that is spread to dogs and cats by mosquitoes. An infected mosquito will bite and inject larvae under your pet’s skin. These larvae mature over 6-8 months becoming adult worms and migrating through the organs to the heart and blood vessels of the lungs. Just one bite has the potential to cause infection.

Unfortunately, mosquitoes are everywhere in Mackay. They even find their way into most houses, this means that even indoor pets are at risk of infection from heartworm.

Initially no signs of infection are seen as heartworm is usually an insidious slow onset disease (months or a couple of years may pass before signs are seen). When symptoms do appear, they are usually signs of heart failure. The earliest signs may be shortness of breath, loss of stamina, exercise intolerance or a nagging cough. As the disease progresses, breathing becomes more difficult, the abdomen may distend with fluid and your pet will be lethargic, lose weight and often stop eating. If left untreated, heartworm is nearly always fatal.

Usually, there are few clinical signs in cats and the main sign is sudden death, sometimes after the cat coughs up blood. One or two heartworm infecting a cat are normally enough to be fatal. To make things worse there is no treatment for heartworm in cats so prevention is the only way to protect them!

A simple blood test can be performed at our clinic for the presence of heartworm. Because of the long breeding cycle of heartworm two tests (six months apart) may be required to give your pet the ‘all clear’.

Heartworm is very common in Mackay. Almost all dogs over the age of 8 months become infected with heartworm if prevention is not provided.

Heartworm can be treated if your dog is diagnosed with the disease. However, it is not without its risks as the treatment used can cause allergic reactions in some dogs and have serious side effects.

It is recommended puppies should start prevention from 12 weeks of age with Andergrove Veterinary Clinic as we offer a heartworm injection that will reach back the first 3 months to birth to fully protect them.


Treatment 1 - 12 weeks - Initial Proheart Injection
Treatment 2 - 6 months - Booster Proheart Injection
Treatment 3 - 15 months - Annual Proheart Injection

Older Dogs

Dogs older than 8 months with unknown heartworm prevention history will require in-clinic testing prior to the commencement of heartworm prevention.
Andergrove Veterinary Clinic sends regular reminders for heartworm injections for complete protection all year round. Please phone us if you have a query regarding the heartworm status of your dog or cat so we can provide you with the necessary information. 
Alternative preparations such as monthly tablets and spot-ons are available to protect your dog against heartworm, however by far the most convenient and compliant prevention is an injection administered by Andergrove Veterinary Clinic.
Cats can be given monthly tablets or spot-on treatments to prevent heartworm and should start as early as 8 weeks of age and continued monthly for life.
Please phone us to discuss the best heartworm prevention for your pet