Ask the Vet: Take to Heart

Do inside pets need heartworm protection?


Weekly Newsletter

The best of The Saturday Evening Post in your inbox!


Question: If heartworms are transmitted by mosquitoes, which live outside, why would my veterinarian recommend my indoor-only cat Sydney be treated with a heartworm preventive?

Answer: Heartworms are transmitted by mosquitoes, but it’s not unusual for them to find a way indoors. Starting a heartworm preventive could protect Syd from severe breathing problems and premature death.

One heartworm or even some immature larvae can cause heartworm-associated respiratory disease (HARD). Symptoms include coughing, wheezing, lethargy, and vomiting.

Diagnosis requires many tests, and even then, accurate diagnosis is difficult. Therefore, HARD is often misdiagnosed as asthma.

Unfortunately, the arsenic treatment that kills heartworms in dogs is toxic to cats, so treatment options for cats are limited.

Fortunately, many safe, effective, easy-to-use feline heartworm preventives are available. Ask your veterinarian to prescribe one of them to protect Syd.


Ask the Vet is written by veterinarian Lee Pickett, VMD. Send questions to [email protected] and read more at

This article is featured in the May/June 2024 issue of The Saturday Evening Post. Subscribe to the magazine for more art, inspiring stories, fiction, humor, and features from our archives.

Become a Saturday Evening Post member and enjoy unlimited access. Subscribe now


Your email address will not be published. Required fields are marked *