Heartworm Disease In Cats

Heartworm disease is currently an important issue in dogs in Ontario. What about cats?

Heartworm is a blood parasite that is passed from animal to animal by mosquitoes. During the summer months it may be transferred to a susceptible animal. Fortunately, cats are much less susceptible than dogs to developing infection and are much less likely to show outward signs of disease. Unlike dogs, cats will also often clear their own heartworm infection, although not necessarily before it causes a problem. It is interesting and important to note that up to one third of affected cats are kept strictly indoors.

What signs of heartworm disease might you see?

Adult heartworms live in the heart and therefore tend to cause problems related to the heart and lungs. Clinical signs may include coughing, trouble breathing, lack of energy, nosebleeds, collapse and sudden death as well as more general signs including vomiting, weight loss, and neurological abnormalities (head tilt, blindness, seizures). Any animals exhibiting one or more of these signs should be examined by a veterinarian.

Because of the range of signs that can be seen with heartworm disease it is a much more difficult disease to diagnose in cats than in dogs whose signs are restricted more or less to the heart and lungs. Heartworm blood testing is available, but is also much more complicated in cats than in dogs and must usually be supported by other evidence of infection. It is important for all owners of cats who die or are humanely euthanized due to signs that could be related to heartworm disease consider a post mortem to help determine how widespread heartworm disease is in cats in Ontario. We know that it is here, we just don't know how many cats it is currently affecting.

As for preventative medication, each animal is an individual and as such, owners should discuss preventative programs with their veterinarian. Remember that your veterinarian is your pet health specialist.