Our team continues to be here for you and your cherished pets. We are OPEN and are now able to provide a wide range of services. To learn more about the changes we have implemented in response to COVID-19 and what to expect during your next visit, click here.

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Heartworm Treatment

By Dr Jennifer Merry BSc(Agr) DVM

Spring is here – which means soon we will begin testing Ontario dogs for heartworm. The blood test is taken 6 months after the last possible date of exposure the year before. In this area, that means April 15.

Due to a large selection of easy to administer monthly heartworm prevention, we do not see many heartworm positive dogs, and that is lucky because heartworm is difficult and expensive to treat.

If a dog has a positive heartworm test, the first step is to repeat the test. We don’t want to start this process until we are sure – and false positives do happen occasionally. Then the dog’s blood is looked at under a microscope to see if any microfilaria (baby heartworm) can be seen. The more there are the more dangerous the treatment. And this may change how quickly we want the treatment to occur. Dogs will then have complete bloodwork done to ensure there is no preexisting damage to internal organs that may affect the drugs chosen. Then, chest x-rays are taken to check for changes to the heart and lungs.

Medication that kills adult heartworms is not effective in worms under 4 months old so a strict schedule has to be created to maximize effectiveness while minimizing risk.  Many heartworms have bacteria themselves which add to the heartworm disease so dogs are treated for twice daily for 4 weeks with an antibiotic to decrease this risk.  Heartworm medication is started at the same time to reduce new infections and eliminate existing susceptible life-stages (larvae). At this time steroids are started and exercise restriction enforced to protect against a violent immune reaction to the dead and dying worms.  This is the part that many owners find the most difficult: no exercise – at all – for the next 3 months. Leash walks and cage rest only.

The medication used to kill the adult worms is given in 3 separate doses 1 month apart. It is given deep into the back muscles and so the dog is sedated each time  to prevent motion or discomfort.  Three months after beginning, another heartworm test is done to test for effectiveness of the treatment.

Heartworm is a serious disease affecting dogs. It is easy to prevent and really difficult to treat, so see your veterinarian to start your dog on seasonal prevention that is right for your lifestyle.


Radiograph of Brayden the Cat

What lies beneath... the Benefits of Dental Radiographs

There are many signs of dental disease such as tartar, gingivitis, bleeding, not eating. Sometimes your veterinarian can see a tooth that’s loose or that the enamel is damaged. The tricky part is that teeth are like little icebergs and much of the tooth is below the gum line.

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Last updated: June 1, 2020

Dear Clients,

With recent changes to restrictions on businesses, we are pleased to advise that effective May 15, 2020 some restrictions on veterinary practices have been lifted. Based on these changes, below are some important updates to our operating policies.


This includes vaccines, wellness exams, blood work, heartworm testing, spays and neuters, dental services, and more!



If you wish to connect with a veterinarian via message, phone or video, visit our website and follow the "Online Consultation" link.


Have you welcomed a new furry family member to your home? We’d love to meet them! Visit our Must Know New Pet Owner Information page for useful resources and helpful recommendations for new pet owners.


We are OPEN with the following hours:

Monday to Friday: 7:00 am - 7:00 pm
Saturday & Sunday: 9:00 am - 3:00 pm


If your pet requires grooming, please give us a call and we will put your name on a list. Our groomer Stephanie will contact you directly to schedule an appointment.


As of Tuesday, May 19, 2020, Country Tails Doggie Daycare is open! Their temporary hours of operation are 8:00 am - 6:00 pm. You may get touch with one of our daycare team members at (905) 690-8005 or at countrytails@clappisonvet.com

Thank you for your patience and understanding and we look forward to seeing you and your furry family members again!

- Your dedicated team at Clappison Animal Hospital