Here's why:
* Preventative, not a treatment: Heartgard and similar medications are designed to prevent heartworm infections by killing the larvae (microfilariae) before they mature into adults.
* Adult worms are too large: These medications are not strong enough to kill adult heartworms, which are much larger and have a different life cycle.
* Treatment requires different medication: If a dog has already contracted heartworms, a separate treatment involving a series of injections and medications is necessary to kill the adults. This treatment is lengthy, costly, and potentially risky for the dog.
It's crucial to:
* Keep your dog on preventative medication: This is the best way to protect them from heartworms.
* Have your dog tested annually: Even if your dog is on preventative, annual tests can help detect any missed infections.
If you suspect your dog may have heartworms, contact your veterinarian immediately. Early diagnosis and treatment are essential for a successful outcome.