Swan Valley Veterinary Clinic

Box 388
Swan River, MB R0L 1Z0



What is Heartworm?

Heartworm is a serious and sometimes fatal disease for pets. Heartworm is a parasitic worm that lives in the heart of animals. It most commonly affects dogs. It can cause major damage to the heart, lungs and blood vessels, leading to lung disease, heart failure and other organ damage. This worm is transmitted by mosquitoes. When a heartworm positive dog is bitten by a mosquito, the microfilaria (baby worms) that are in the blood stream are ingested by the mosquito. When that mosquito then bites another dog, that microfilaria can be transferred between dogs. Once infected, it takes approximately 6 months for the baby worms to mature into adults. There is something you can do to prevent it! Set up an appointment with us to test for heartworms. If the test is negative, pick up prevention medication!

Signs of Heartworm

In early stages, there are not obvious clinical signs. As disease progresses, signs you might see include a mild persistent cough, not wanting to exercise, lethargy after moderate amounts of exercise, weight loss and loss of appetite. Heart failure and sudden blockage of blood flow are the most severe symptoms and are life threatening.

How to Diagnose Heartworm and Where is it Found?

Heartworm is diagnosed using a blood test that detects the presence of adult heartworms in the body.  It takes about 15 minutes to get results of the test.

Heartworm infection used to just be a southern Manitoba health concern.  In the last few years, we have seen positive cases in central and northern Manitoba.  Heartworm testing and prevention for dogs is now recommended throughout Manitoba.

What Do I Do if my Dog is Heartworm Positive?

Heartworm is treatable in dogs. It can be extensive and expensive. Once a dog has been determined heartworm positive, additional diagnostics such as x-rays, ultrasounds, and additional bloodwork are required. The treatment for heartworm involves a series of injection and oral medication.  Treatment takes months.  During and after treatment, strict rest is essential to prevent further complications.



Heartworm can be prevented using specific medications, such as Heartgard or Nexgard. It is required to do a heartworm test before starting prevention medications as doing prevention medications with a heartworm positive dog can cause health complications. The test we do is simple.  It involves collection of a blood sample, a 15-minute wait. If the test result is negative, prevention can start immediately!  Call us today to book your dog in for Heartworm testing and to pick up the preventative medication!