Heartworms in Dogs - What You Don't Know That Can Hurt Your Pooch

Mar 11th 2011

Heartworms in dogs are easy to prevent but difficult and costly to cure. Our friends at WebMD Healthy Pets asked Sheldon Rubin, 2007-2010 president of the American Heartworm Society, to separate facts from the myths about heartworm infestations in dogs.

Q: How do dogs get heartworms?
A: Only by the bite of an infected mosquito. There's no other way dogs get heartworms. And there's no way to tell if a mosquito is infected. That's why prevention is so important.

Heartworm disease has been reported in all 50 states. And the bite of just one mosquito infected with the heartworm larvae will give your dog heartworm disease.

Heartworm disease has not only spread throughout the United States, but it's also now found in areas where veterinarians used to say, "Oh, we don't have heartworm disease." Areas like Oregon, California, Arizona and desert areas -- where irrigation and building are allowing mosquitoes to survive. And if you have mosquitoes and you have animals, you're going to have heartworms. It's just that simple.

It takes about seven months, once a dog is bitten by an infected mosquito, for the larvae to mature into adult heartworms. They then lodge in the heart, lungs and surrounding blood vessels and begin reproducing. Adult worms can grow up to 12 inches in length, can live five to seven years, and a dog can have as many as 250 worms in its system.