Can my cat get heartworm?

Photo by Ramiz Dedaković on Unsplash

A common question we get: What does heartworm have to do with our feline fur-iends?

The lifecycle of heartworm in cats

Adult heartworms will produce heartworm larvae in an infected animal. When a mosquito bites the infected animal, it takes in the larvae. Once an infected mosquito bites a cat, the infective larvae are deposited into the cat’s bloodstream. Unlike dogs, cats are not natural hosts of heartworm. Therefore, the larvae are less likely to grow to adulthood in cats. Cats normally have a smaller number of heartworms than dogs.

Does this mean that heartworm is not dangerous for cats?

It is still dangerous for cats to get heartworm! In fact, the heartworm larvae and adult heartworms cause a much more severe reaction in cat’s heart, lungs and blood vessels than in dogs! Also, the blood vessels in cats are much smaller than in dogs. Thus, even 1-2 heartworms can be fatal in cats.

That is alarming! How is heartworm diagnosed in cats?

The “4dx SNAP test” is commonly used to diagnose adult heartworm infections in dogs. It is much more difficult to diagnose heartworm in cats, as cats have a lower heartworm count that is less likely to show up on the “SNAP test”. Thus, veterinarians have to do many more tests (e.g. blood count tests, Xrays, heart ultrasound) to diagnose heartworm in cats.

What are the signs of heartworm in cats?

Some affected cats may have no clinical signs. However, if there are clinical signs, they can be more severe than in dogs. Cats can have acute or chronic symptoms. Symptoms include:

  • Coughing
  • Lethargy
  • Weight loss
  • Vomiting
  • Difficulty breathing

In chronic, untreated cases, cats can develop heart failure and have a bloated abdomen from excessive fluid. Some cats can show signs of brain damage like seizures, blindness and head tilt. Some cats can even die suddenly, with no symptoms beforehand.

My cat looks healthy – do I really have to start him/her on heartworm prevention?

Heartworm prevention is important in cats, as it is very difficult to diagnose and treat. Ironically, it is more hassle-free to start cats on heartworm prevention than in dogs, as cats do not need any heartworm test before starting on heartworm prevention!

How do I get my cat started on heartworm prevention?

There are two spot-on products that protect against heartworm in cats – Revolution for Cats and Broadline. You can order this from ZumVet by following this link.