Heartworm is only transmitted by the bite of an infected mosquito. There’s no way to tell if a mosquito is infected, which is why prevention is very important. It takes about seven months from when the dog or cat is bitten for the larvae to mature into adult heartworm.
They then reside in the heart, lungs and surrounding blood vessels and begin reproducing, causing severe lung disease, heart failure and damage to other organs in the body. 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!
Why does my dog need a heartworm test?
Heartworm tests are required to verify that dogs do not have heartworm before we can give out any prevention medication such as Revolution and Heartgard. Giving these medications to a dog that tests positive for heartworm can be lethal. No medication is 100% effective!