Heartworm in dogs

Heartworm disease is a debilitating and potentially fatal disease which affects thousands of dogs each year. Left undiagnosed or untreated, heartworm disease can lead to heart failure and death of your pet. Prevention of heartworm infection is an important part of looking after your dog’s health.

Where is it found?

Heartworm is spread only by mosquitoes and occurs in most of the Australian mainland, although it is more prevalent in warmer, wetter regions of northern Australia. Since the availability of effective and convenient preventative medications in the mid-1980s, the incidence of heartworm has declined, but vets continue to diagnose heartworm infections in dogs in many parts of the country.

Heartworm disease

Adult heartworms may grow up to 30 cm long and live inside the heart chambers and the main blood vessels of the lungs where they interfere with circulation and damage the tissues. Adult heartworm produce offspring called microfilariae, which circulate in the infected animal's blood.

When a mosquito bites an infected pet, ingests blood containing the microfilariae. After spending about two weeks in the mosquito, the microfilariae turn into infective larvae. The infective larvae are transmitted through the skin when the mosquito bites another pet, moving into the bloodstream and then migrating to the heart and lungs, where they mature.


Canine heartworm


Heartworm disease is typically not recognised until the disease is quite advanced. Common signs of heartworm disease include coughing, shortness of breath, weakness, weight loss and listlessness.

If not detected and controlled with proper treatment, advanced infections with heartworm can lead to congestive heart failure and may eventually lead to death. 

Your vet can perform a simple blood test that can reliably detect heartworm infection. In many regions, this may be the only test needed before starting a preventive program. If the dog shows heartworm symptoms or has visited a known heartworm problem area, additional X-rays and other sophisticated laboratory tests may be used to detect heartworm disease. Prompt detection and early treatment are vital to a successful cure, although some cases will require surgery. Treatment usually involves several days in the veterinary hospital and can be expensive.

Control of heartworm

Whilst heartworm disease is an extremely difficult disease to treat, it is very simple to prevent with the help of EXELPET™ products. Regular use of a preventative medication prevents recently acquired heartworm larvae from developing into adult heartworms. Puppies should be started on the preventative program at six weeks of age and continued year round.

Dogs that are not currently on a heartworm prevention product should be tested to determine their infection status prior to using a preventative. Severe or fatal reactions may occur if preventative medicines are given to dogs with an existing heartworm infection.

Heartworm preventatives come in chewable, topical and injectable formulations provide for added convenience, and some also control additional internal and external parasites. Preventative medications may be administered year-round or at least within one month after the animal's first exposure to mosquitoes and continued until at least a month after the end of the mosquito season. 

EXELPET™ Heartworm products

Heartworm Treatment

EXELPET EXELPET EZY-DOSE Monthly Heart Worm All Dogs 4 chews-70

EXELPET™ EZY-DOSE™ Monthly Heartworm Treatment for Dogs 

Flea Intestinal & Heartworm

EXELPET EXELPET Vet Series Monthly Flea, Intestinal & Heartworm Treatment for dogs 4-10kg 1 x 1mL-70 (1)

EXELPET™ VET SERIES™ Monthly Flea, Intestinal & Heartworm Treatment For Dogs 4-10kg


EXELPET EXELPET Vet Series Monthly Flea, Intestinal & Heartworm Treatment for dogs 10-25kg 1 x 2.5mL-70 (1)

EXELPET™ VET SERIES™ Monthly Flea, Intestinal & Heartworm Treatment For Dogs 10-25kg


EXELPET EXELPET Vet Series Monthly Flea, Intestinal & Heartworm Treatment for dogs over 25kg 1 x 4mL-70 (1)

EXELPET™ VET SERIES™ Monthly Flea, Intestinal & Heartworm Treatment For Dogs Over 25kg

Heartworm & Intestinal Worms

EXELPET EXELPET EZY-DOSE Monthly Heart & Intestinal Wormer Dog 4 chews-70 (1)

EXELPET™ EZY-DOSE™ Monthly Heartwormer + Intestinal All-Wormer for Dogs

What to do if you forget to give a dose

If a dose is missed, then immediate administration of the missed dose and resumption of regular dosing will minimize the opportunity for the development of adult heartworms. When switching between heartworm prevention products the first dose must be given within a month of the last dose of the former medication. As a safeguard, many veterinarians recommend annual or biannual screening tests even for dogs that are on heartworm prevention. If you have any doubts or questions about a missed dose, please contact your veterinarian.

Travelling with your dog

It is most important to maintain heartworm prevention while travelling. If you live in an area where heartworm does not normally occur, and are planning to travel to a heartworm area, you will need to start your dog on preventative medication before you leave home. In any doubt you ask your vet for an annual heartworm test to check your dog’s heartworm status.