6 Important Facts About Heartworm Disease in Cats


Heartworm disease can be found in many animals like cats and dogs and is caused by an infestation of the organism Dirofilaria immitis. This organism is a parasitic nematode (roundworm) which is also called a heartworm. Because the severity of heartworm disease may vary from animal to animal and can be potentially fatal in extreme cases, it’s important to understand more about this disease so you can provide the best care for your pets.

Cause of heartworms

The cause of heartworm disease is pinpointed to mosquito bites. Mosquitos are known to carry the infective heartworm larvae which can enter the body if a mosquito feeds on an animal. Mosquitoes get immature heartworm larvae by feeding on an infected animal which develops inside of that mosquito before being transmitted to the next animal. It’s important to note that one infected cat cannot infect another cat and heartworms can only be transmitted by mosquitoes.

What is the life cycle of a heartworm?

Heartworms begin their life cycle once they enter an animal’s body through mosquitoes as larvae before they turn into worms. When larvae enter an animal’s bloodstream, it migrates to the right side of the heart and the pulmonary arteries. It is here that these larvae mature into adult heartworms and reproduce. It’s good to note that while heartworm larvae can be very dangerous in cats, more than 90% of infective larvae do not make it to adulthood because cats have a very robust immune system.

Signs and symptoms of infection

According to the AVMA, signs of possible heartworm disease in cats include coughing, respiratory distress, and vomiting. Other common symptoms include weight loss, decreased energy, and changes in breathing patterns. Unfortunately, the diagnosis of heartworm infection is more difficult to determine in cats than in dogs, but there are a series of different tests your veterinarian may be able to run to help you determine the likelihood of heartworm disease.

How to determine that your cat has heartworm disease

In general, the AVMA states that both antigen and antibody tests are recommended for cats to give the best chances of detecting the presence of heartworms. Antigen tests check for the actual parasite and antibody tests check for the animal’s response to the parasite. In some extreme cases x-rays and eosinophil counts may be conducted to help determine if your cat is infected with heartworm disease but in order to establish which test is best for your pet, it’s important that you consult your veterinarian.

Best treatments of heartworm disease

Treating heartworms can be very tricky and while it’s easily done with a drug for dogs, it’s a lot more challenging for cats because they have been known to have serious side effects from these drugs. Instead, veterinarians might choose to treat the symptoms of heartworm disease. Since heartworms have a much shorter lifespan in cats than dogs (2-3 years as opposed to 5-7 years), it may be possible for cats to outlive the worms and have minimal side effects. For severe signs of the disease in cats, it may be necessary to surgically remove the heartworms.

How to prevent heartworms

While controlling mosquitoes and preventing mosquito bites may be an impossible task, there are prevention drugs that make it easy to prevent heartworm disease from happening in the first place. Even if your cat doesn’t spend much time outside, it’s possible for infected mosquitoes to enter your home, and these drugs can be a major tool in preventing the disease in your cat.

If you are adopting a new cat and are looking to prevent heartworm disease or if you have an older cat who is showing signs and symptoms that may mirror those of heartworm disease, it’s important that you consult a licensed veterinarian. At Bregman Veterinary Group we make it our mission to help you determine the best course of action for your pet so that they can live long, healthy lives. To schedule an appointment for your cat, click here to get started.

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