Heartworm Prevention in Pets – Why It’s Important

Heartworm prevention is a critical part of your pet’s regular wellness program. You dogs and cats are part of the family, so regular annual wellness exams are as important for them as they are for you. Part of any wellness exam and plan should include a discussion about heartworm prevention.

We’ve seen two dogs test positive for heartworm in just the last two weeks at Compassionate Animal Care. Unfortunately, the latest American Heartworm Society survey in 2018 found that incidence of heartworm has been trending up rather than down, with the number of infected dogs per clinic rising by 21% in the U.S. and its territories between 2013 and 2016.*

With the unusually wet winter we’ve had in the metro Phoenix area, we can expect an above average mosquito season this year. Mosquitoes thrive in places that are warm throughout the year.


Photo by Егор Камелев on Unsplash

Although we typically don’t have a moist climate, we do have regular incidences of standing water – often through overwatering of community landscaping or abandoned pools. Pool abandonment caused a major mosquito problem during the housing crisis 10 years ago. Green pools led to an increase in mosquito activity that we still suffer from today.

Some of our most frequently asked questions about heartworm disease in Arizona:

What is heartworm?

Heartworm is a large parasitic worm – up to 14 inches long – that, in adulthood, lives in the heart and pulmonary arteries of an infected dog.

How can my pet contract heartworm?

Heartworm is a parasite transmitted by infected mosquitoes.

What are the symptoms of heartworm disease?

Coughing, shortness of breath/panting, easy tiring/intolerance of exercise, fluid accumulation in the abdomen or chest, nose bleeds, and at worst, sudden death. Not all of these symptoms necessarily occur in the same dog, nor is there necessarily a progression. An infected dog may have no symptoms at all, or may develop any of the signs on the list at any time. It takes five to seven months for a young heartworm to become detectable by blood test.

Heartworm prevention – what should I do?

Heartworm can be prevented with oral, topical, or injectable preventatives. You may have seen commercials for some of the major brands: Heartgard, Sentinel, Interceptor, Revolution and more. Consult your veterinarian. A heartworm test is needed before medication can be issued.

Should a puppy be given heartworm preventative?

The younger you can start a pet on a heartworm preventative the better. Consult with your veterinarian, but puppies as young as six weeks can be started on some products. An annual heartworm test will be required before medication can be issued, whatever the age of your pet.

Can cats get heartworm?

Yes, cats are also susceptible to heartworm if they are bitten by an infected mosquito. However they are not as prone to infection as dogs. Cats are considered more resistant to heartworms because the worms don’t thrive as well inside their  bodies. You can read more detail here: Heartworm Infection in Cats

I have an indoor cat; do I need to get it tested?

Both indoor and outdoor cats are at risk for heartworm disease. Heartworm is transmitted by mosquito bite. We all know that these pesky critters can make their way in to our homes, so even if your pet is indoors mostly, mosquitoes can still get in.

When is mosquito season in Phoenix?

Our mosquito season usually starts in earnest early in the year, around March, and can last all the way through the Holidays. But it’s not unusual for mosquitoes to be found all year round, especially when we’ve had above average rainfall like this past winter. That’s why you need to be prepared to treat your pet year round.

Where can I find more information?

At Compassionate Animal Care we follow the American Heartworm Society’s recommendations. The first link will take you there. Veterinary Partner is also a great source of information on heartworm.

Schedule an Appointment Today

Of course, the best way to learn more about heartworm prevention and treatment is to talk to your veterinarian. Call 480.774.6995 to schedule an appointment with Compassionate Animal Care today.


* https://www.heartwormsociety.org/newsroom/in-the-news/511-american-heartworm-society-releases-2018-canine-heartworm-guidelines

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