mosquito pic

Heartworm Disease


Heartworm is a parasite transmitted through the bite of a mosquito. Microscopic larvae will then grow into very large adult worms within the chambers of the heart and the large vessels surrounding the heart. If left untreated this is a potentially life threatening disease, resulting in congestive heart failure and even death. The treatment options are very risky, painful and expensive therefore prevention is our most important tool in combating this disease.         

 We are fortunate in Canada that our winter season causes a die off of the mosquito population every year and many animals are on monthly preventives – there are fewer opportunities for disease to spread and our infection rates remain relatively low. We are however living in a more global society and many people are traveling with their pets to warm climates for parts of the year and rescue groups are adopting out animals from all over the world. We have therefore seen a steady increase in infection rates across the GTA over the past 10 years.

There are a variety of monthly preventative heartworm medications available, from oral chews to topical treatments.Some of the heartworm medications also treat for other common parasitic infections such as roundworms, hookworms or fleas. Heartworm preventives are administered monthly from June 1st through to November.