Can Cats Get Heartworms?
As a pet owner, it’s essential to recognize the potential illnesses and diseases your beloved companion could contract. One of the most common and severe illnesses that dogs can get is heartworm disease. Can cats get heartworms as well?
Heartworms may not be as common in felines as they are in canines, but they’re still cause for significant concern. If you’re worried about your pet’s health, connect with one of our experienced veterinarians at Revel Vet in Queen Creek, Arizona, and review our comprehensive guide on feline heartworm disease below.
What Is Heartworm Disease?
Heartworms can lead to heartworm disease, which is a serious and often fatal condition in pets.
Heartworms can grow to be a foot long in maturity. When they enter a host animal, the parasites will establish themselves in the animal’s heart, lungs, and associated blood vessels. Their presence within these organs can trigger heart disease and lung failure, but heartworms can impact other bodily organs as well.
These worms are a problem for many mammals, including:
- Dogs
- Cats
- Foxes
- Coyotes
- Wolves
- Sea lions
Although rare, there are instances of heartworms infecting people. However, their natural host is the dog. Canines can become infected, and the parasites will mature into adulthood, mate, and produce offspring. Infected dogs can have hundreds of worms in their bodies, creating lasting damage.
Can cats get heartworms? Unfortunately, the answer is yes. The good news, however, is that felines are atypical hosts, so the worms usually don’t last until adulthood.
The Life Cycle of Heartworms
Before delving more into feline heartworm disease, it helps to learn about the lifecycle of the potentially dangerous parasite that causes it. Here is what you should know:
- A mosquito bites an infected mammal and picks up heartworm larvae or microfilaria.
- The microfilaria will transform over 10 to 14 days inside the mosquito, becoming three different forms of larva.
- After molting for a third time, the larva can infect another mammal via a mosquito bite.
- In cats, the heartworm larva stays in the animal’s tissues for three to four days before molting again and residing in the cat’s tissues for about two months.
- The larva finally turns into an immature adult and escapes the cat’s tissues through its bloodstream.
- The parasite settles in the pulmonary arteries, which are responsible for transporting blood without much oxygen from the heart to the lungs for re-oxygenation.
- The immature heartworm adult develops into an adult heartworm in a pulmonary artery over a period of four to six months, during which it may release microfilariae into the cat’s bloodstream, initiating the process again.
Mature heartworms can live five to seven years in dogs and up to two or three years in cats. The more mosquito bites the pet gets while infected, the more worms it can host.
How Does the Disease Spread From One Animal to Another?
As the lifecycle of a heartworm suggests, the transmission of the disease occurs through mosquito bites. If an animal has an adult heartworm in its body that releases microscopic microfilaria into its bloodstream, the mosquito can pick it up when it bites the infected mammal. The insect then passes larvae to another animal when it feeds.
The bite itself doesn’t transmit the parasite. In other words, the transmission doesn’t occur while a mosquito is actively feeding on a cat or dog.
Instead, the insect picks up the microfilaria during a feeding and drops it onto another possible host’s skin during another feeding. The microfilaria then enter the animal through the bite wound.
What To Know About Feline Heartworm Disease
Although heartworm disease in cats differs from that in dogs, it is still a serious condition that pet owners should be aware of.
Feline heartworm disease is one of the worst conditions a cat could experience. It impacts their overall well-being and could threaten the cat’s life. Even if the parasites aren’t mature, they can still complicate the cat’s health.
About 60 to 100 days after the infection begins, the cat will start experiencing symptoms. The presence of immature worms in small pulmonary arteries in the lungs triggers a severe inflammatory response that affects not only the arteries but also the bronchioles and alveoli, the small airways and air sacs, respectively.
Will the disease affect a pet cat’s heart? The answer is not as straightforward as you may think. While the disorder can compromise the heart’s function to some extent in cats, the main problem is with the pulmonary arteries and lungs.
The disorders that heartworms cause are mainly due to their size. These foot-long, spaghetti-like parasites can damage the walls of pulmonary arteries in dogs, preventing blood from flowing freely through them and putting excessive stress on the heart.
In some cats, a heartworm infection may disappear suddenly due to the animal developing an immune system response strong enough to kill the worms. Yet, the immune response can also be severe enough to affect a cat’s health and well-being.
Stages of Feline Heartworm Disease
When it comes to cats, heartworm disease falls into two stages. Stage one occurs when the immature adult heartworms reach the pulmonary arteries and begin to die. Their presence triggers a sudden inflammatory response that veterinarians sometimes misdiagnose as a respiratory disease, like asthma.
Because of how the condition affects cats, veterinarians and researchers refer to the inflammatory response as heartworm-associated respiratory disease, or HARD. When the surviving worms reach maturity, the inflammatory response becomes less severe. The change is primarily due to the adult worms suppressing the animal’s immune system.
Next is stage two, which happens whenever adult heartworms die. Their death can cause a severe inflammatory and anaphylactic response, which is often fatal. This problem occurs because the dead worms trigger a massive pulmonary inflammatory cascade, which impacts the cat’s small, narrow blood vessels.
A consequence of mature heartworm death is embolism. Although embolisms aren’t always fatal, they can be. If a cat survives, they will likely have permanent lung damage, as well as chronic respiratory disease.
Is Your Cat at Risk of Infection?
Since you know the answer to “Can cats get heartworm disease?” you may wonder whether your beloved pet is at risk for infection. Even if heartworm disease doesn’t seem to be a major concern for your area, it’s something to be wary of.
Some communities experience higher rates of heartworm infection than others. So, even if it’s not a big problem around your neighborhood, if you and your pet travel to a heartworm hotspot, their chances of infection can increase substantially. Stray dogs, wolves, foxes, and coyotes are hosts, so it’s reasonable to assume heartworm disease is prominent wherever they are.
You also have to consider the traveling habits of mosquitoes, which are the only carriers of this parasite. The wind can blow these insects to different regions, where they can infect a new batch of mammals. It’s not uncommon for a previously unaffected area to become a hotspot for the disease.
There are documented cases of heartworm disease in all 50 states, affecting both indoor and outdoor pets. So, while some areas are more prone to infection than others, it’s impossible to say that the condition is only in one region. That’s why the general recommendation for cat and dog owners is to have their pets tested annually for heartworms and administer a heartworm preventive medication once every 12 months to protect them.
How To Recognize Heartworm Disease in Cats
Not all cats with heartworm disease will share the same symptoms at identical severities. In fact, some cats may not display clinical signs at all. The most noticeable health problems and symptoms stem from the sudden death of adult heartworms or the unusual migration of the worms.
So, if your pet shows signs of possible infection, what could you expect? The most common signs of feline heartworm disease include:
- Coughing
- Open-mouth breathing
- Reduced appetite
- Lethargy
- Breathing difficulties
- Exercise intolerance
- Weight loss
- Vomiting
- Neurologic abnormalities like seizures or difficulty walking
- Heart murmur
- Sudden death
Heartworm Diagnosis and Treatment: What To Expect
Feline heartworm disease requires a professional diagnosis from a veterinarian. However, diagnosing the condition is more difficult for a cat than it is for a dog. As such, vets use several methods, including the following, to diagnose feline heartworm disease:
- Microfilaria testing: This method sometimes produces false negatives because cats seldom have circulating microfilaria in their bloodstream.
- Antibody blood testing: This blood test is effective in detecting immature infections around two months after the initial mosquito bite. Unfortunately, it doesn’t detect the presence of adult heartworms, and antibody testing can produce a positive result even after a cat clears the infection.
- Antigen blood testing: The ideal method for diagnosing heartworms is the antigen blood test. Yet, it only identifies the presence of female heartworms, which can be a problem for cats, as felines typically have all male worm burdens.
- Echocardiography: This ultrasound test produces a visualization of a cat’s heart, showing live worms within the right side of the heart and the animal’s pulmonary artery. It’s also ideal for identifying abnormal pulmonary pressures.
- Chest X-rays: In some cases, this kind of imaging can help veterinarians diagnose feline heartworm disease because the condition enlarges pulmonary arteries. It can also change the appearance of lung tissue.
Unfortunately, no test will provide a 100% accurate diagnosis. Instead, the testing can suggest the presence of heartworm infection. Also, the condition is not curable in cats. Most treatments for canine heartworm disease, including merbromin, are toxic to cats.
If your cat doesn’t have any clinical signs of infection, the vet may monitor them over time for spontaneous resolution. Otherwise, the veterinarian may prescribe prednisolone, ivermectin, or other medications to assist with respiratory distress and inflammatory responses.
How To Protect Your Pet From This Parasite
Can cats get heartworms? They absolutely can. Since there is no definitive treatment for feline heartworm disease, prevention is the best way to keep your pet healthy and safe. There are plenty of heartworm medications available that are safe for cats.
Ideally, you should start administering preventive medication for your kitten when they’re about eight weeks old. The treatment lasts for 12 months, so you will need to administer it every year.
Learn More About Heartworm Disease in Cats at Revel Vet
The answer to “Can cats get heartworm disease?” is, unfortunately, yes. While the condition is less common in cats than in dogs, it is still potentially fatal and therefore warrants preventive medication.
If you notice respiratory symptoms, lethargy, decreased appetite, and other symptoms of common parasites in your pet, don’t hesitate to bring them to Revel Vet in Queen Creek, Arizona. Our team of skilled veterinarians provides comprehensive wellness services for pets, including physical exams, vaccinations, diagnostics, and pharmacy services.
Rest assured that your furry friend will be in good hands with us. To schedule an appointment at Revel Vet in Queen Creek, call (480) 701-8609.
FAQs About Feline Heartworm Disease
At Revel Vet, we understand how concerning a serious condition like heartworm disease can be for pet owners. Consult our answers to common questions on the topic below.
Will Cats Live a Long Time With Heartworms?
If cats have heartworms, they can live with the condition for two to four years. Most cats clear the infection on their own within that time, but sudden death is also a possibility.
How Rare Is Feline Heartworm Disease?
In comparison to heartworm transmission in dogs, the infection is rare in cats. Still, the parasites can trigger severe, potentially fatal health problems for cats.
What’s a Good Heartworm Treatment for Infected Cats?
Unfortunately, there is currently no reliable treatment for cats infected with heartworms. Veterinarians may recommend additional care and support at an animal hospital if the condition is advanced enough.
Can Cats Get Heartworms If They Never Go Outside?
The infection comes from mosquito bites. Indoor cats can contract heartworms even if they never go outside, as mosquitoes can enter homes and transmit the disease.
