Heartworm Disease is on of the most common diseases in dogs in Florida and other states across the U.S. Heartworms are carried by mosquitoes and only takes one bite to infect our pets. This disease is treatable and preventable, however, left untreated it can be fatal. The worms travel through the blood stream and into the heart where they become adults and continue to grow. As they grow, it makes it harder for blood to flow properly causing pet to have difficulty breathing and they go into congestive heart failure.