Can My Cat Get Heartworm?

 The answer is a resounding “yes.”  You may have thought heartworm disease only affects dogs, but unfortunately cats can be infected with heartworm as well.  The cat is not a natural host for the heartworm parasite, Dirofilaria immitis, and so the microscopic immature heartworm larvae, called microfilaria, often do not grow into adult heartworms.  If they do reach maturity, there often are only a few adult heartworms in each infected cat.  That means fewer and smaller worms survive causing false negative heartworm test results and making accurate diagnosis more difficult. 

Heartworm disease in cats can have serious consequences and prevention is the key.  Both the immature microfilaria and the adult worms cause the cat’s body to set up an immune reaction to kill the developing worms.  This immune reaction causes lung damage, or Heartworm Associated Respiratory Disease (HARD), resulting in asthma-type symptoms or even sudden death.  Moreover, the medication used to treat heartworm-infected dogs cannot be used in cats, so prevention is really the only means of protecting cats from HARD. Once infected, the only recourse is to manage your cat’s symptoms, which may require long term medication and even hospitalization if symptoms are severe.   The following signs may indicate that your cat has been infected:

• Persistent cough
• Breathing difficulties (panting, wheezing, rapid or open-mouthed breathing)
• Depression
• Loss of appetite
• Weight loss
• Sporadic vomiting
• Lethargy
• 
  

If your cat exhibits any of these symptoms, please call us right away at (203) 775-3679 to schedule an appointment. 

Next week, look for Dr. Salvatore’s piece on heartworm prevention in cats, and why it’s important for even our indoor cats to be protected. 

By Rachael Chandler, CVT

 Rachael Chandler is a certified veterinary technician and is one of two feline advocates we have on staff.  Please feel free to give Rachael a call for tips on making your cat’s visit to our office easier, or to ask any general cat care questions.  You can also visit our website at www.BrookfieldAnimalHospital.com and look under the “Services” tab for other cat care tips.

What is Heartworm Disease?

Heartworm disease is a serious, potentially-fatal disease seen in pets in the United States as well as other parts of the world.  Heartworm disease is caused by heartworms (Dirofilaria immitis), which are parasites that can grow to be one foot long within an infected animal.  These parasites live in the heart and the blood vessels that carry blood from the heart to the lungs, and they can cause severe lung damage and heart failure.  In addition to dogs and cats, heartworms can live in other mammals, such as wolves, coyote, and foxes. These wild animals can serve as a source of infection for our pets.

The mosquito is essential in the transmission of heartworm.  Adult female heartworms living in an infected dog, fox, coyote, or wolf produce microscopic immature worms called microfilaria which circulate in the bloodstream.  When a mosquito bites an infected animal and takes a blood meal, it picks up these microfilaria.  Over the course of 10-14 days, the microfilaria mature into an infective stage of larvae within the mosquito.  After maturation occurs, when that mosquito bites a dog, cat, or susceptible wild animal, the infective larvae are able to enter the new host.  Once inside the new host, it takes approximately six months for the larvae to mature into adult heartworms.  Adult heartworms can live for five to seven years in dogs and up to two to three years in cats.  The longer an animal is infected, the more likely it will show signs of disease.  The signs of heartworm disease can vary in dogs and cats but often relate to damage to the heart and/or lungs.  These signs can be as subtle as a loss of appetite, or as severe as sudden death.  We will discuss the signs in more detail in a future post. 

Heartworms are present in all 50 states, and the American Heartworm Society estimates that over one million dogs in the United States are currently infected with adult heartworms.  Because infected mosquitoes can get inside your home, both indoor and outdoor pets are at risk.  Prevention is the key to keeping your pet healthy and safe from heartworm disease.  A variety of safe and effective preventives are available for both dogs and cats.  Look for more blog posts later this month written by our staff members to learn more about heartworm disease and what we recommend to prevent it, or call our office at (203) 775-3679 for more information.

By Michael Dattner, DVM

Michael Dattner, DVM, along with his wife, Silke Bogart, DVM is the owner of Brookfield Animal Hospital.  Please click here  to read his complete bio.