There are two broad categories of worms that may affect our pet dogs and cats, heartworm and intestinal worms.  Please see our intestinal worm page for more information.




Heartworm, or Dirofilaria immitis, is a parasite that is spread by mosquitoes, so you pet does not even need to be in contact with other pets to become infected.


Life cycle.


Heartworm has a complicated life cycle.  Infected dogs have microfilaria, an immature form of heartworm, circulating in their bloodstream.  Microfilariae are sucked up by mosquitoes when feeding on the blood of infected dogs. The immature parasite develops into a heartworm larva inside the mosquito, then a single bite from a carrier mosquito can infect your pet (dog, cat or ferret). As the worms mature in the heart they can cause a physical blockage as well as thickening of the heart and associated blood vessels.  In the early stages of infection there may be no visible signs, however, infection may eventually lead to signs of heart failure (reluctance to exercise, lethargy, coughing) and even death. Heartworm is present throughout most of Australia (except Tasmania and arid areas).



What are the signs of infection?


  • weight loss
  • lack of appetite
  • coughing
  • laboured breathing
  • exercise intolerance
  • collapse in extreme cases.


How is heartworm diagnosed?


There are several types of blood tests available that enable us to physically look for microfilaria in the blood or test for the presence of heartworm in your pet. Radiographs (x-rays) can reveal changes to the heart and lungs that are typical of heartworm disease in extreme cases.


Can heartworm be treated?


Heartworm can be treated. The type of treatment depends on the nature of the case and can range from simple medical treatment to surgical intervention in severe cases. Fortunately at our clinic we haven't had to treat a case of heartworm for over 20 years. Prevention has proven to be a success in controlling this parasite.


Since the disease was first diagnosed in Goulburn over 20 years ago, a successful heartworm prevention programme carried out by pet owners under the advice and guidance of veterinarians means that today the incidence of heartworm in the Goulburn district is very low. In fact, Australia as a whole has had one of the most successful heartworm prevention programmes of any country. This doesn't mean that the disease has been eradicated. Far from it. The success of prevention of infection in dogs has seen the parasite shift its focus to cats and ferrets in some of the areas where the disease is still quite prevalent. As with vaccinations against viral and bacterial diseases, heartworm prevention is an on-going part of your pets health care programme.


How can heartworm be prevented?


Thankfully, heartworm is very easy to prevent and should form an integral part of your pet health care routine. We have very effective preventative treatment options available including tablets, chews, spot-on's and even an annual injection for dogs administered by one of our vets. Because of the low incidence of the disease we do not currently recommend prevention programmes for cats and ferrets however if you intend to move to a new district where heartworm may be more common we advise pet owners to talk to a veterinarian in the new area, find out how the disease is behaving in that area and then ask us for advice on what to do for your pet cats and ferrets before moving.


If your pet has not been on heartworm prevention and comes from an area where heartworm is a major problem we strongly recommend a heartworm test prior to starting a prevention program, followed by a repeat test 6 months after commencing.


Please call us to discuss the best heartworm prevention for your pet.