Heartworm disease is a serious parasite-borne condition that can impact your cat's health, resulting in heart failure, lung disease, and even death. Here, our Boulder vets explain why the prevention of this disease is so important. 

What is heartworm in cats?

Heartworm disease is primarily is caused by a parasitic worm called Dirofilaria immitis which is spread through the bite of a mosquito.

Cats, dogs, and ferrets can become this parasite's 'definitive host' after being bitten by an infected mosquito.  This means that while living inside your pet, the worms mature, mate and produce offspring. Heartworms live within the blood vessels, lungs, and heart of an infected pet and can cause significant damage. 

How common is heartworm disease in cats? 

Although cats are relatively resistant to heartworm infection when compared to dogs, the disease can still occur. Even indoor cats are susceptible with 1 of every 3 cases of heartworm disease in cats found in cats that are indoor only. 

Symptoms of Heartworm Disease in Cats

Heartworm disease in cats can be difficult to diagnose because there are no specific clinical signs. The most common symptoms are the sudden onset of coughing and rapid breathing. Unfortunately, these symptoms can also be attributed to a wide range of other conditions. Other signs of heartworm disease in cats include weight loss and vomiting. 

Sadly, heartworm disease can be fatal in cats. Sometimes cats that had no previous symptoms can suddenly develop severe respiratory distress or die. It is thought that this happens due to a reaction in the lungs to young heartworms or from heartworms, dead or alive, entering pulmonary arteries and blocking blood flow to your cat's lungs. 

How does the vet check my pet for heartworms?

Your veterinarian can detect the presence of heartworm through blood tests done at the vet's office. The vet will examine your pet's blood for signs of antigens produced by heartworms.

These antigens can be detected approximately 5 months after your pet has been bitten by an infected mosquito, but not before. 

Can heartworm in cats be cured?

There is no drug approved for treating heartworm in cats. One of the drugs that is available for dogs with heartworm has been used in cats but causes significant side effects, including acute lung failure. Due to the severity of the side effects this treatment is not recommended. 

There are two options for helping a cat with heartworms. 

1. Treat the symptoms in hopes that the cat outlives the worms. Heartworms live in cats for 2-3 years (as opposed to 5-7 in dogs). Symptom management treatment is a long, difficult process. It involves continual medication and periodic oxygen treatment if the cat is in acute distress. In many cats, this treatment can reduce their symptoms and improve their quality of life but the risk of sudden death or respiratory failure still exists as the treatment doesn't directly target the heartworms. 

2. The heartworms can be surgically removed. Unfortunately, up to 40% of cats may die during or after this procedure, so surgery is only recommended for those cats who have severe disease and a poor prognosis without surgery. 

How can I prevent my pet from getting heartworm disease?

Prevention is the best protection. It is now recommended that all cats, indoor and out, be placed on a monthly preventive medication. It is much easier, safer, and cost-effective to prevent your feline friend from developing heartworm in the first place than to try and treat it. 

Is your cat showing signs of heartworm disease? The veterinary cardiologists at Rocky Mountain Veterinary Cardiology have extensive experience in treating a wide range of cardiac conditions. Request a referral from your vet today or contact us for more information.