Heartworm disease is caused by a parasitic worm that lives in the heart, lungs, and surrounding blood vessels of infected dogs. They can grow up to 12 inches long, and in severe cases, a single dog can harbor hundreds of worms at once.
The damage heartworms cause isn't just from the worms themselves, it's from the years of inflammation, scarring, and strain on the heart and lungs as the body tries to fight them. Untreated heartworm disease is progressive and eventually fatal.
The important thing to know: heartworm disease is almost entirely preventable. Simple monthly (or semi-annual) medications are safe, affordable, and nearly 100% effective.