Humane Society of Central Illinois


The Threat:

Dogs are infected with heartworms when they are bitten by an infected mosquito. There is no way to detect that a mosquito carries the heartworm larvae, so prevention is key to keep your dog safe. Easy and inexpensive to prevent but costly and, possibly deadly to treat, every dog owner should take the threat seriously.

Once a dog is bitten by an infected mosquito, the larvae mature into adults within seven months. 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.

Mature heartworms damage the heart and blood vessels, and if left untreated, the dog faces a good chance of dying.

The Treatment:

The drug that is used to treat heartworm is called Immiticide. It's an injectable, arsenic-based product. The dog is given two or three injections that will kill the adult heartworms in the blood vessels of the heart. The typical treatment cost is $1000 but recent shortages of Immiticide have made it even more costly and difficult to treat.

After treatment, the worms begin to die. And as they die, they break up into pieces, which can cause a blockage of the pulmonary vessels and cause death. It is vital that the dog is kept quiet during the treatment and then for several months afterward. Studies have shown that most of the dogs that die after heartworm treatment do so because the owners let them exercise. It's not due to the drug itself.

The Prevention:

For less than a weekly trip to Starbucks, dogs can receive the necessary prevention of heartworms. A year's supply of heartworm preventative will cost about $35 to $80, depending on a dog's weight. Commonly used heartworm preventatives include Heartgard, Heartgard Plus, Interceptor, and Iverhart. For the best protection, veterinarians recommend that dogs receive preventative all year-round, not just in the warm, summer months.

When a dog is protected and is bitten by an infected mosquito, the larvae is immediately killed and prevented from forming into an adult making it a safe, guaranteed way to protect your pet. If you are not currently giving your dog preventative, please contact your vet to begin the process of assuring your dog the longest, healthiest life possible.

HSCI Manager