What is heartworm disease in cats?
Heartworm disease is a serious, potentially fatal disease in cats in the United States and many other areas in the world. It is caused by the heartworm, a blood-borne parasite that lives in the heart or the nearby blood vessels of infected cats. While female worms measure about 6 to 14 inches long (15 to 36 cm) and a half-inch wide (3mm), males are about half the size of a female.
So, if you've ever asked yourself, "Do cats get heartworm disease?", the answer is a resounding "yes."
How common is heartworm in cats?
Though heartworm disease is diagnosed more often in dogs than cats, it's possible for cats to become infected, and both indoor and outdoor cats are at risk. Heartworm disease in cats is very different from heartworm disease in dogs, and most worms in cats do not survive to the adult stage. Cats typically have fewer adult worms than dogs (usually one to three).
What are signs and symptoms of heartworm disease in cats?
Many cats affected by heartworms have no adult worms, which means heartworm disease often progresses undiagnosed. Even immature worms can cause significant damage and lead to a condition known as heartworm-associated respiratory disease (HARD).
Heartworms can even migrate to other parts of the body such as the eye, brain, or spinal cord. Potentially severe complications include lung inflammation and blood clots in the lungs, which can occur when adult worms die in the cat's body.
Subtle or apparent symptoms of heartworm disease can appear. There are few, if any, early signs. Some symptoms your cat may experience include:
- Asthma-like attacks
- Fluid accumulation in the abdomen
- Weight loss
- Difficulty walking
- Periodic vomiting
- Lack of appetite
- Coughing
- Exercise intolerance
- Difficulty breathing
- Increased breathing
- Open-mouth breathing
- Neurological abnormalities
- Heart murmur
- Fainting or seizures
It is critical to seek emergency veterinary care as soon as a cat shows any signs of respiratory distress, including open-mouth breathing.
Is heartworm in cats fatal?
Tragically, in some cases, the first sign of heartworms in cats is collapse or sudden death.
What causes heartworm disease?
After a mosquito feeds on an infected cat, the mosquito picks up immature heartworm larvae that develop for 10 to 30 days inside the mosquito's gut before entering its mouth parts. The infected mosquito then bites another cat and injects its infected larvae.
These larvae move through the bloodstream to the pulmonary arteries and the heart's right side, where they grow into adult heartworms and reproduce within about six to seven months. About eight months after a cat has been infected, a new group of larvae are born and live in the cat's blood for about a month.
While dogs may have several hundred heartworms in their bodies, few of these larvae are typically found circulating in this area by the time cats are tested. Most do not survive to the adult stage in cats' bodies, since cats are not natural hosts.
Is heartworm in cats contagious?
Heartworms are transmitted through mosquitoes – not directly from one cat to another or from an infected dog to a cat. The risk of infection is highest when mosquitoes are in the environment and are actively feeding. Indoor cats are not immune; an infected mosquito can easily get into a house and infect a cat.
Can heartworm disease in cats be cured?
Medication used to treat heartworm infections in dogs cannot be used in cats. Therefore, while this condition can be managed in cats there is no clinical treatment. Prevention is the only means of protecting cats from the effects of heartworm disease.
How is heartworm disease in cats treated?
Because heartworm disease is serious and progressive, the earlier your cat is tested and diagnosed, the better. The. type of treatment your cat will require will depend on their symptoms. As noted above, any signs of respiratory distress warrant a veterinary emergency and should be treated right away.
If your cat is displaying more subtle symptoms, your veterinarian will take a small sample of your cat's blood, which will then be tested for heartworm proteins. If your cat tests positive, further tests may be ordered, and X-rays or ultrasounds (echocardiography) may be required.
Treating heartworm infections in cats is risky. While the heartworms may be effectively treated, they can cause permanent damage. If worms have been found in the lungs, your vet may recommend bringing your cat in for chest X-rays every 6 to 12 months.
If mild symptoms are detected, small doses of prednisolone (a synthetic corticosteroid) may be needed to reduce inflammation. This drug is typically used as a short-term method of managing symptoms as it can cause adverse reactions.
Your primary vet may refer you to our internal medicine specialists at VRCC, for advanced diagnostics and treatment. A board-certified internal medicine specialist can work with your veterinarian and our other in-house specialists to ensure your cat receives the best care. We offer a range of services, including respiratory medicine.
Severe heartworm disease could require your cat to be hospitalized at our facility in Englewood so our team can administer supportive care for acute periods of respiratory distress and shock.
Our veterinary specialists can also administer antibiotics, intravenous fluids, drugs to treat organ issues. Because of the difficulty associated with medical management of heartworm disease in cats, surgery is the preferred method of treatment.
A more invasive surgery requires a vet to use forceps to directly remove worms through the heart. However, all forms of surgery for heartworm in cats can lead to circulatory collapse and death.
How can I prevent heartworm disease?
Cats should receive year-round heartworm preventives to be taken orally on a monthly basis in areas where mosquitoes are active, starting at eight weeks of age. Where mosquitoes are seasonal, preventive measures should be taken for at least six months each year. Prevention is safe and easy.
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.