Most of us are familiar with heartworm disease in dogs, but did you know that our feline companions are also at risk? The life cycle of the heartworm is essentially the same in dogs and cats. It all starts with a single innocuous bite from an infected mosquito that transmits a microscopic worm (microfilaria) into their bloodstream. Over the next several months those tiny worms grow up into adult heartworms and make their home in the unsuspecting animal’s heart.

Cats, in contrast to dogs, are more resistant to contracting heartworm infection. That said, testing for the disease in cats is unreliable prior to crisis, clinical signs are minimal, and, upon infection, there is no safe treatment.  An adult worm can live undetected by the cat’s immune system for years. Upon death of that worm, that camouflage is lost, resulting in a severe immune reaction and the production of a clot in a highly sensitive area of the body which often leads to sudden and unexpected death.

I was inspired to write this blog in response to a particular case that came to my attention a few months ago.  My husband is a veterinary pathologist (a pathologist studies the cause and effect of disease in the body and can sometimes help diagnose disease in the case of an unexplained death).  He was called to perform a post-mortem exam on a presumed healthy, four year old local cat who had suddenly died. According to her owners, she was fine until they noticed her cough up a significant amount of blood and then she passed away before they could even get her to the emergency hospital.  When my husband did the examination he found one, single, dead heartworm in her heart. She had no other signs of disease. A sudden death like this feels traumatic and I felt terrible for this kitty’s family. Heartworm disease in cats is not on many of our radars, here in Colorado, and this particular kitty spent most of her time indoors!  In honor of this kitty, I resolved to get the word out to our clients about the risks of heartworm disease, in Colorado, in dogs AND cats.

The best news is that heartworm disease is TOTALLY PREVENTABLE.  It is not always easy to get our kitties to take oral medication (understatement of the year) and so we have a new product we are excited to carry at Westside Animal Hospital.  Bravecto Plus is a topical product that prevents heartworm disease, fleas, ticks and intestinal parasites – and you only have to apply it every 2 months. For our pups we are still relying on our monthly oral heartworm prevention chewable treat, Milbegard, and you can combine it with a topical application of Bravecto every 3 months to add protection from fleas, ticks and intestinal parasites.  Heartworm season in Colorado is April/May through September/October but for those of you that travel throughout the year it is best to use prevention year-round. Let us know how we can help you prevent heartworm disease in your dog or cat.

Authored by Dr. Kelly Hutchison