How Common is Heartworm in Australia?

Heartworm is a parasitic worm that lodges in the heart and vessels. It is easy to prevent but difficult to treat. How common is it and is your pet really at risk?

The simple answer is YES, your pet is definitely at risk of heartworm if it is not up to date with its parasite treatments.

Heartworm is certainly less common than it has been in the past, however we are far from eradicating this dangerous disease. For anyone who has seen the picture of the heart full of worms in their vet’s office, it is pretty clear why it’s called heartworm. Unfortunately, heartworm infected dogs don’t tend to show obvious signs until they start coughing up blood or suddenly die, so early detection and prevention are our key strategies for keeping pets safe.

How is heartworm spread?

Heartworm is spread by mosquitoes, so even indoor dogs that don’t mix with other dogs can get heartworm. For the disease to be spread, a mosquito must bite a heartworm positive dog and then bite your dog, which is why having all pets on heartworm prevention greatly reduces the spread of the disease.

Can other species get heartworm?

Luckily humans can’t get heartworm, but cats, ferrets, foxes and dingoes all easily pick up heartworm from mosquitoes too. For cats, just one heartworm tends to be fatal. For foxes and dingoes living on the fringes of urban areas, their heartworms act as a reservoir for the disease, which is why we will never entirely get rid of it.

How do I know if my pet has heartworm?

If you have had a break of more than 3 months in your heartworm prevention, ask your vet for a simple heartworm test. Dogs with heartworm tend to cough and lose weight gradually, but only when the heart damage is irreversible. Back when heartworm was common, sudden death or coughing up blood were often the only indicators the dog was suffering.

How common is heartworm?

A study in shelter dogs from NSW, QLD and SA in 2009 found a prevalence of between 0-2.2% infection rate in this population of dogs. Warm weather, humidity and floods will increase mosquito populations and encourage the spread of heartworm. It is thought that heartworm infestation rates in stray dogs, dingoes and foxes are higher than 2%. Since there are often large populations of untreated animals that live on the fringes of urban areas, they act as a reservoir for the infection. Mosquitoes, depending on the species (there are over 400 species in Australasia!) can travel for up to 50km, so although heartworm is rare, mosquitoes are not!

So should I use heartworm prevention?

Yearly heartworm injections or a monthly preventative like Interceptor are the best way to prevent heartworm infection. These are incredibly cheap and safe treatments, so are recommended year-round in Australia. The disease is costly to treat and usually fatal by the time it’s diagnosed so prevention is MUCH better than cure.

What if my pet has never had a heartworm preventative?

Visit your vet for a heartworm test first. Pets with established heartworm disease can have an acute anaphylactic reaction to a treatment if they happen to already have the disease. Although this is incredibly rare, it is a pretty cheap test to do and if heartworm is diagnosed at this early stage, the treatment is much safer than if heart damage has already occurred.

So what next?

If you own a cat, dog or ferret and are not sure about whether your heartworm treatment is up to date, pop into one of our Vet Clinics and we can check any treatments you are giving and do a heartworm test if required.