Does my cat really need heartworm prevention?

Our question this week was:

Dr. Debra – I have two indoor only cats. I live Columbus Ohio. Do my cats really need heartworm prevention?


Rob S. – Columbus, Ohio


Hi – thanks for your email Rob. You wrote asking if your two indoor only cats need heartworm prevention. The answer is – if you want to keep your cat safest – the answer is yes. Heartworm (HW) disease is an important and common parasitic disease of dogs and cats. It is more common in dogs. HW disease is caused by Dirofilaria immitis, a large thin worm that lives in the lung blood vessels, just outside of the heart. This worm can grow to be 6 to 15 inches in length and live for up to five years. Mature adult heartworms produce microscopic offspring or microfilaria that circulate in the blood.

There is no effective treatment in cats. As little as one to two worms can cause signifigant illness and even death. Because of this, heartworm prevention is recommended. Discuss it with your veterinarian based on the risk in your area.

An article that might be helpful to you is Heartworm Disease in Cats. Another article that might be useful is Heartworm Prevention Guidelines for Cats.

Best of luck!

Dr. Debra

To read most recent questions Click here!

Click here to see the full list of Ask Dr. Debra Questions and Answers!