Heartworm disease in Dogs

What is heartworm disease

Heartworm disease is one of the most devastating canine illnesses, yet is completely preventable.  Difficult and costly to treat, a heartworm infection leads to many restless nights for pet parents as well as injections, hospitalization, lab work, and pain medications for the dog.  In Australia, with warm weather, humidity, and a high incidence of flooding, heartworm-carrying mosquitoes are prevalent.  Here, the facts about heartworm infection will be explored, as well as reasons why dog owners should be preventing heartworm year-round.

Heartworm is a blood-borne parasite that is spread by mosquitoes.  Contrary to popular belief, mosquitoes are not natural hosts for heartworm; rather, mosquitoes spread the disease by biting a heartworm positive dog, and then subsequently biting a healthy dog, therefore comingling the blood of the two pets.

heatworm lifecycle

Once heartworms have been spread to a dog, they continue to grow and reproduce, living for 5 – 7 years.  They move through the bloodstream, but are particularly dangerous in arterial areas, where they can easily clog or constrict blood pathways and work themselves into other organs, such as the lungs.  Some Heartworms can even grow up to 14 inches long!  A heartworm infection is particularly dangerous for small dogs, and only a handful of heart-worms can quickly cause serious problems, including death.

Often, heartworm is not detected in dogs until the infestation is serious.  Infected dogs will cough or wheeze during exercise, suffer increased fatigue, vomit, have a decreased appetite, and gradually lose weight.  When heartworm damage is severe, dogs will display serious cardiovascular distress, including fainting, seizures, laboured breathing, pale gums, and bloody urine.  Coughing up blood is another common indicator of heartworm.  Once these symptoms appear, immediate action is necessary.

Heartworm Prevention injection and Tablets

The best way to prevent heart-worm is to use a monthly heart-worm tablets. Puppies can be  administrated heartworm injection from the age of 6 months of age. This will be followed by an additional booster at 15 months of age after which your dog will be required to have a yearly booster for life. In Australia, approximately 2.2% of dogs not on a regular preventative will develop heartworm disease.  Although this number appears small, the percentage is directly correlated to the number of pet owners that are protecting their dogs against the disease.  The more dogs that are protected, the less of a chance the disease will spread.  The risk of heartworm will never decrease to 0%, however, because foxes and dingoes are also carriers for heartworms.  Additionally, even if heartworm is not prevalent in one region of the country, the chance of infection is not completely mitigated.  Mosquitoes can travel a long distance – up to 50 km – which makes them prolific enemies in the fight against heartworm.

Heartworm injection cost

Cost for the injection vary as doses are giving according to the weight. It’s between $110 – $190 which of course is only once a year.  Cost of testing for heartworms would be around $55, but some vets do this for free when  you book for the injection, it would take around 5 minutes to get the results and you need drop of pet’s blood


Why All year around treatments?

Owners should also be aware that heartworm preventatives must be administered year-round, and not only during the summer months when mosquitoes are at their worst.  Heartworm preventatives work by killing infections already present in the larval stage; therefore, discontinuing preventatives the moment cold weather appears could leave your dog defenseless against a growing infection.  In addition to controlling heartworm, most preventatives control other parasites, such as roundworm, hookworm, fleas, tapeworm, and whipworm as well.  Before starting a heartworm preventative, be sure to have your dog tested for heartworm disease, as administering a preventative to an infected dog could result in serious side effects, including death.