Health Topics

Heartworm Disease

What is heartworm disease?

Heartworm disease is a disease that affects a dog's heart and other main organs and is transmitted solely by mosquitoes. When a dog already infected with heartworm is bitten, the mosquito takes up immature baby worms(microfilariae), as well as blood.

Over 10-14 days, these worms grow into larvae and are transmitted to others dogs by the mosquitoes. These larvae eventually travel to the new dog's heart where they mature and complete the life cycle by producing new microfilariae. This method of transfer of the disease, from dog to dog, allows heartworm to spread fairly easily and with very little detection.


Unfortunately, by the time symptoms of heartworm become apparent, the effects on internal organs may be too advanced to be treatable. Typical signs of the disease are:

  • Chronic cough
  • Laboured breathing
  • Premature fatigue
  • General lack of energy
  • Reduced appetite
  • Weight loss
  • Heart attack after exertion


Simple blood test: Snap 4DX Test can detect four infections (Lyme disease, Anaplasmosis, Ehrlichiosis, Heartworm disease) in one blood sample in less than 10 minutes.


Once your veterinarian has examined and diagnosed heartworm in your dog, he/she can begin treating your dog. Adult heartworm can be killed through a series of injections or in an emergency, removed through surgery.

After several weeks, another series of medication is given to eliminate microphilariae from the animal's bloodstream. Once microphilariae have been removed, your pet can be put on a heartworm preventative.


There is no vaccine available to prevent infections but there are methods of prevention that are nearly 100% effective. Daily or monthly medication that destroys the early stages of the parasite soon after it enters your pet is the most common method. This medication usually comes in the form of a pill. Since an animal's weight and geographic location must be taken into consideration, only your veterinarian can help you choose the right medication and prevention schedule for your pet.