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The Importance Of Heartworm Prevention

Heartworms are extremely serious and potentially fatal to all dogs, cats, ferrets, and other mammals. They are spread only through the bite of an infected mosquito. People cannot get heartworms from heartworm positive dogs or infected mosquitoes. The infected mosquitoes carry heartworm larvae, and transmit the heartworm to your pet through a bite. There isn’t a way for you to tell if a mosquito is a carrier of heartworm larvae. If you live anywhere that has a mosquito population, your animals are at risk for heartworms. Even if your dog is outside short amounts of time, your dog is at risk- if there are mosquitoes present. It takes roughly six months after a dog is bitten by an infected mosquito, for that larvae to become an adult. Once they are mature adults, they begin reproducing.

Heartworms damage the heart and blood vessels. Adult heartworms can grow up to 12 inches (over years) and can lodge in the heart or blood vessels. Left untreated, it will lead to an animals’ death. As the heartworm infestation progresses, a dog will develop symptoms as the heartworms crowd the heart and lungs. The most common symptom is a cough, but becoming winded or less active are also reported. In severe cases, dogs can lose consciousness from not having enough blood supplied to the brain, and also retain fluids.

Heartworm prevention eliminates the heartworm larvae that are introduced into an animals’ system, and stop them from becoming reproducing adult heartworms. Sadly, heartworm positive animals are quite common, especially in shelters, but are not contagious to other animals and are still able to be adopted (and continue heartworm treatment at home). After an animal has been successfully treated for heartworms, they are still at risk for infestation, and need to remain on a heartworm preventative.


Heartworm prevention is offered in monthly pills, monthly topical ointment that are applied to the skin, and also a six-month injectable product. There are also combination products that protect against fleas, ticks, and intestinal parasites (can also become life threatening). Your veterinarian can help you choose the right product for your companion. The cost varies by the weight of your dog and product to product.

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