This is a serious disease that shouldn’t be taken lightly. Heart-worm disease is caused by foot-long worms (heart-worms) that live in the heart, lungs and blood vessels associated with these organs. They can cause heart failure, severe lung disease and damage to other organs in the infected pet.

How do animals get heartworm?

Both cats and dogs are affected by this type of disease, although in cats it is more difficult to treat. Pets can get infected with heartworm by a mosquito bite. When a mosquito that is infected bites a pet, it then transfers heartworm larvae into the body. Now the larvae move into the animal's heart or pulmonary arteries.

When the larvae have matured, the female heartworms start producing small, immature worms that are called microfilaria. These small immature worms circulate in the bloodstream. This explains why the mosquito can transmit this disease. The mosquito will bite an infected animal and transmit it to other animals through the bloodstream.

Particularly severe problem for cats

Cats do not typically transmit this kind of disease to others and are usually the end hosts. One of the most serious symptoms of heartworm disease in cats is sudden death. Heartworm disease is the second most common cause of sudden death in cats.  

The problem with this disease in cats, is that it is hard to tell whether the cat has it. Cats may have heartworm disease but it gets mistaken sometimes for something else like hairballs, chronic cough, lethargy and vomiting. Some cats show signs of asthma-like symptoms. This is called heartworm associated respiratory disease (HARD). Although it costs a fortune, this problem can be managed.

Some cats don’t show any signs of heart disease but have it. This is why they suddenly just drop dead. Although cats don’t suffer the bigger burden that dogs do with far more worms in the body, specialists say one worm is enough to cause permanent damage. Prevention is the best cure and keeping your pets living area mosquito free is a good place to start.

Can heartworm be prevented? 

Keeping pets indoors can help to prevent infection, but does not remove the risk altogether. Studies have shown that 25-30% of cats with heartworm disease are indoor-only. The great news is that chewable meds that can prevent heartworm in pets are available. As your veterinarian for more information and keep your heartworm prevention program up to date.