What is Heartworm in Cats?
Heartworm disease is mainly caused by the parasitic worm Dirofilaria immitis, which is spread through a mosquito's bite.
Cats, dogs and ferrets can become a definitive host for this parasite if they're bitten by an infected mosquito. This means that the worms mature while living inside your pet, mate and produce offspring. Heartworms live in the blood vessels, heart and lungs of an infected pet and may cause severe damage.
How Common is Heartworm Disease in Cats?
It's true that cats are not as susceptible to heartworm infection as dogs are. However, the disease can still occur in cats. Even indoor cats can contract heartworm disease, with 1 of every 3 cases found in cats that live exclusively indoors.
Symptoms of Heartworm Disease in Cats
Heartworm disease in cats can be challenging to diagnose as there are no specific clinical signs. The most common symptoms include sudden onset of rapid breathing and coughing. Unfortunately, a range of other conditions also come with these symptoms. Weight loss and vomiting are two more symptoms of heartworm disease in cats.
Is heartworm in cats fatal?
Sadly, heartworm disease can be fatal to cats. Sometimes, cats that had no previous symptoms may suddenly develop severe respiratory distress and die. A reaction in the lungs to young heartworms, or heartworms that are dead or alive entering the pulmonary arteries and blocking blood flow to the cat's lungs may be to blame.
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 Heartworms 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.
Our board-certified veterinary cardiologists at VSEC diagnose and treat heart disease and other cardiac conditions in cats and other small animals.
Is heartworm in cats contagious?
No, heartworm in cats is not contagious. Heartworms' natural hosts are dogs, not cats. The parasites do not reproduce inside cats. Mature heartworms living in a dog's heart and tissue can produce baby heartworms (microfilariae), which are then spread by mosquitoes.
How Can I Prevent My Cat 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.
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.
Do Indoor Cats Really Need Heartworm Prevention?
Even if your cat is mainly an indoor cat, she should still be on heartworm prevention. No home is 100% insulated from the outside, and mosquitoes can get into the house. Plus, your indoor cat may still spend even a bit of time outside, if unintentionally.
Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.