Heartworm disease is primarily caused by a parasitic worm called Dirofilaria immitis that spreads through bites from infected mosquitoes.
Cats, dogs, and ferrets can become the 'definitive host' of this parasite after being bitten by a mosquito that is infected. This means that while living inside your pet, the worms mature, mate and produce offspring. Heartworms live within the blood vessels, lungs, and hearts of infected animals and can cause serious damage.
How Common Heartworm Disease Is Among Cats
Compared to dogs, cats are relatively resistant to heartworm infection, but they can still get this disease. Even indoor cats are susceptible, 1 of every 3 cases of heartworm disease are found in indoor cats.
Signs & Symptoms of Heartworm Disease in Cats
It can be difficult to diagnose heartworm disease in cats 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's thought that this happens as a result of a reaction in the lungs to heartworms, dead or alive, entering pulmonary arteries and blocking blood flow to your cat's lungs.
Diagnosing Heartworm Disease in Cats
Your veterinarian can conduct blood tests in their office to detect the presence of heartworms. The vet will examine your cat's blood for signs of antigens produced by heartworms.
These antigens can be detected approximately 5 months after your kitty has been bitten by an infected mosquito, but not before.
Can Cats With Heartworm Be Cured?
There are no drugs approved for treating heartworm disease in cats. One of the drugs that are available for dogs with heartworm has been used in cats but causes significant side effects, including acute lung failure. This treatment is not recommended because of the severity of the side effects.
There are two options available for helping cats with heartworm disease.
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 cats that have severe cases and a poor prognosis without surgery.
Preventing Heartworm Disease in Cats
Prevention is the best way to protect your cat. Monthly prevention medication is now recommended for all indoor and outdoor cats. It is much easier, safer, and cost-effective to prevent heartworms than it is to try and treat them.
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.