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By June 1, 2024 June 12th, 2024 Newsletter

Heartworm season is right around the corner!

By Drs. Leigh & Bronwyn Chisholm

As the days continue to get longer and warmer, we look forward to spending more time outside soaking up the sun. Tick season is already in full swing, but that is not the only pest we need to be mindful of. With warmer days, which allow us to enjoy walks through the park, camping trips, and time spent in the great outdoors, we also must expect the arrival of mosquitoes, and heartworm season.

Heartworm disease is a serious and potentially fatal disease. It is caused by a blood-borne parasite called Dirofilaria immitis, more commonly known as heartworm. Heartworm disease does not spread directly from dog to dog, but instead is transmitted through the bite of an infected mosquito. As many as 30 species of mosquitoes can transmit heartworm. Once a pet is infected by a heartworm-positive mosquito, tiny heartworm larvae enter their body. These larvae then travel through the small blood vessels, heading to the heart. It can take up to 6 months for them to reach the heart, where, as adult worms they grow large and numerous enough to block the main vessels leading out of the heart. Once fully developed, heartworm disease is risky and complicated to treat.

Both dogs and cats are susceptible to being infected by this parasite, and despite it being more common in dogs, cats are not in the clear. Due to a cat’s small size, it takes very few heartworms to cause significant disease. Unfortunately, there is no way to effectively test if a cat has contracted heartworm disease, and therefore is challenging to diagnose. As a result, the best way to keep your pets safe against heartworm disease is through preventative medications.

Lucky for us and our beloved pets, heartworm disease is very easy to prevent. Heartworm season runs in Manitoba from June 1st through to and including November 1st. We recommend giving your pet monthly heartworm preventive medications during this time, such as Heartgard, Nexgard Spectra, or Nexgard Combo for cats. These preventative medications can be purchased from your veterinary clinic. As these are prescription medications, your pet will need to have been seen by your local veterinarian within the past 12 months in order to purchase these medications.

*Check out the YouTube video Dr. Chisholm made titled “How Heartworm Prevention Works” to learn more about these medications!

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