Heartworm is a mosquito borne blood parasite. Adult heartworms live in the heart of an infected host (foxes, wolves, coyotes, or domestic dog) then mate and release microscopic microfilaria (young worms) into the blood stream. When a mosquito bites the infected host, it incubates the young worm for 2 – 3 weeks, then injects into it into the new host. Young worms live under the skin for 1 month then develop gradually as it migrates towards the heart.
Since mosquitos usually die off by late October, we start heartworm testing in mid April. We must wait 6 months since mosquitos were last active as the parasite must be mature to show up positive on the test.
There are NO signs of heartworm infection. Later stages of infection can demonstrate signs of congestive heart failure, so the dog would have trouble breathing, coughing, tire easily, fluid buildup in chest or abdomen. Usually by the time a pet starts showing symptoms, it is too late for complete recovery without permanent heart damage or death.
Medication is not 100% effective. Even if you give your dog their heartworm prevention on time every single month from May to October, there is still a small chance that your dog could contract the disease. We test yearly to ensure that if your dog has contracted the disease we can catch it early and start treatment right away.
Veterinarians are licensed under the College of Veterinarians of Ontario (CVO). There are regulations that require that a veterinarian must have a veterinarian-client-patient relationship and have recent and sufficient knowledge of the animal to recommend and provide treatment, including medications. Dr. Chin requires that all of his patients have had an examination within 12 months before dispensing any medications.
We use a medication called Nexgard Spectra for prevention of heartworm in dogs. It is a chewable tablet given once monthly from May 31st to October 31st. It has the added benefit of also protecting against ticks, fleas, and intestinal worms!