How is Heartworm spread and how do I protect my dog?

You might assume that pets catch heartworm directly from one another, but actually the parasite is transmitted through mosquito bites.

The story goes something like this… a mosquito feeds on an infected animal, consumes the heartworm larvae, and bites an unsuspecting dog. The young heartworms enter the pup’s skin where they spend a few months maturing. Then they make their way through the dog’s bloodstream and into the heart, where they grow up to a foot in length.

Cats can catch heartworm, too, but are unlikely to pass the infection back to another mosquito, as heartworm larvae do not circulate in feline blood.

To protect a dog from heartworm, ask your veterinarian about monthly medication.

– Dr. Larry McDaniel, DVM for the “Purina® Animal Instincts” Podcast Series

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