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 5-7 years, and a dog can have as many as 250 worms in its system.