What are the risks if heartworm is left untreated? - Animal Hospital of Statesville

If we don't prevent heartworm, the chronic lung disease in cats will eventually become resistant to treatment and become fatal. Sometimes that's the only sign that you see is death. The cat has adult heartworm, and it doesn't show any symptoms, and then the owner finds the pet deceased. That, unfortunately, is the first sign that you see with a cat.

Asthma in and of itself as an allergic problem is widespread in cats, also making it tough to diagnose heartworm in cats.

As an aside, we recommend yearly retroviral screening, which are diseases like feline leukemia and FIV, which are for a different day of discussion. But that particular test also tests for heartworm disease as well. We recommend outdoor cats get screened for those diseases, so we're inadvertently screening for heartworm as well. It helps with preparedness for what might happen in the life of that cat if it is positive.