As those that own dogs would already be aware, heartworm is a worm that is transmitted by mosquitoes which lives in the dog’s heart. The worm actually requires to have spent some of its life in a mosquito in order to develop and grow.

The mosquitoes that carry heartworm seem to preferentially prefer to feed on dogs than cats. So do cats get heartworm?

The simple answer is yes, but at a much lower incidence than dogs. It is also more common in the USA than Australia. The cat is not a natural host for the heartworm, so the migrating larval worm injected by the mosquito is unlikely to find its way to the heart. The cat’s immune system is very reactive against heartworm so the larval worms are often killed and the worms never make it to adulthood.

The symptoms of heartworm disease in dogs are related to the heart failure it causes.

In cats this is different – the symptoms are related to the strong immune reaction the cat has against the worm.

Cats develop breathing signs that can look like feline asthma, chronic vomiting and coughing. Sudden death can occur.

If a cat does get heartworm it can be very difficult to diagnose as the routine tests we use for dogs don’t work.

The worms produce proteins that we look for in the dog’s blood, but because the cat’s immune system does such a good job of mopping up these proteins we can’t detect them in the cat. Generally diagnosis is made with x-rays and an ultrasound of the heart.

Just like dogs, a preventative treatment can be given.

The 2 main products are Heartgard for Cats and Revolution (which also treats fleas, some intestinal worms and ear mites).