What is feline heartworm disease?

Feline heartworm disease is caused by a parasite, Dirofilaria immitis, that lives inside the cat’s heart and the arteries of the lungs. Mosquitoes transmit heartworm larvae (microfilaria) from the blood of infected dogs and cats to uninfected cats.

Is my cat at risk?

Previously, heartworm disease was more prevalent in tropical areas but is now widespread over much of Australia, including the eastern states. Although the incidence of heartworm in cats is much lower than in dogs, it is more difficult to detect so your cat is basically at risk wherever heartworm occurs in dogs.

All cats are at risk, however cats that live outdoors are more prone to infection and male cats are thought to be more frequently infected than females.

What are the signs of feline heartworm disease?

The adult heartworms cause inflammation of the arteries in the lungs but the changes are much more severe in cats than in dogs, and death can occur suddenly. Those cats that develop signs usually show attacks of coughing and difficulty breathing. Occasionally neurological signs (unsteadiness, seizures, and blindness) are present due to abnormal migration of the larvae in to the brain. Any unusual coughing fits (like asthma) that keep occurring need to be investigated by your vet to rule out heartworm disease.

How is heartworm disease diagnosed and treated?

Diagnosis can be difficult and includes taking blood samples for testing and X-rays. Treatment is even more difficult and not very safe for your cat, so prevention of heartworm disease is crucial.

How can I prevent heartworm disease in my cat?

As the risk of feline heartworm seems to be increasing and because it is a serious disease, it is recommended to have your cat on heartworm prevention, especially in areas where canine heartworm is a problem.

Preventative medication includes monthly tablets given orally (Milbemax) or a monthly ‘spot-on’ product (Advocate or Revolution) that protects against other parasites including fleas. Your vet will give you the best advice as to which product is best for your cat.