Welcome to the all-new Vetlearn

  • Vetlearn is becoming part of NAVC VetFolio.
    Starting in January 2015, Compendium and
    Veterinary Technician articles will be available on
    NAVC VetFolio. VetFolio subscribers will have
    access to not only the journals, but also:
  • Over 500 hours of CE
  • Community forums to discuss tough cases
    and networking with your peers
  • Three years of select NAVC Conference
  • Free webinars for the entire healthcare team

To access Vetlearn, you must first sign in or register.


  Sign up now for:
Become a Member

Reference Desk

5 Myths About Feline Heartworm Disease

by C. Thomas Nelson, DVM

    April 19, 2012—Many people are still not aware that cats can get heartworms. In fact, less than 5% of cat owners use a heartworm preventive on their pets compared with 50% of dog owners. Do we love our dogs more than our cats? I don’t believe we do. I think cat owners just need to learn about the risk these parasites pose to their pets, and so I’d like to share my top five myths about feline heartworm disease:

    Myth #1: Heartworm Is a Dog's Disease

    Cats are getting heartworm far more often than previously thought. I was a skeptic about the frequency of feline heartworm infection, so I conducted a yearlong study examining shelter cats in the Gulf Coast area. The results certainly got my attention. I found that 26% of the cats had been infected with heartworm larvae at some point in their lives, and I found adult heartworms in 10% percent of the cats. Compare this to the feline leukemia (FeLV) infection rate of 5% and feline immunodeficiency virus (FIV) rate of 6%, and you can see that feline heartworm is much more widespread.

    Myth #2: Indoor Cats Are Safe From Heartworms

    Indoor cats are not impervious to heartworm. A study conducted by North Carolina State University found that 27% of the cats diagnosed with heartworm were inside-only cats. It takes only one mosquito to infect a cat, and because mosquitoes can get indoors, both indoor and outdoor cats are at risk and should receive heartworm preventive medication.

    Myth #3: Heartworms Cause Heart Disease in Cats

    The name “heartworm disease” is a misnomer for cats, as the worm mostly affects the lungs and not the heart. The most common signs of feline heartworm disease are coughing, vomiting and difficulty breathing, but can also include: anorexia, blindness, collapse, convulsions, diarrhea, fainting, lethargy, rapid heart rate, weight loss and sudden death.

    Myth #4: Only Adult Worms Cause Problems

    With dogs, heartworm typically isn’t a problem until the worms reach the adult stage and lodge in the pulmonary arteries and heart. Cats, however, do not need an adult heartworm to show signs of the disease; in fact, larvae are a main cause of the problems. Studies show 50% of cats infected with heartworm larvae have significant damage to the small arteries supplying blood to the lungs.

    Myth #5: It Is Easy to Discover if a Cat Has Heartworm Disease

    Diagnosis is much more difficult for cats than it is for dogs, and tests are not the final word on infections. The tests most commonly used in dogs only detect adult female worms. Since most cat infections do not make it to the adult stage, and those that do may only have male worms, many infections are missed by current testing practices. If your cat is showing signs of heartworm disease, talk to your veterinarian. Treatment of heartworm is often ineffective or problematic in cats. That's why prevention is the very best strategy for controlling the disease.

    For more information, visit www.knowheartworms.org, www.heartwormsociety.org or www.petsandparasites.org.

    Source: Vetstreet, Inc.


    Did you know... Ixodes spp ticks are thought to have expanded their range northward into areas previously too cold to maintain their populations.Read More

    These Care Guides are written to help your clients understand common conditions. They are formatted to print and give to your clients for their information.

    Stay on top of all our latest content — sign up for the Vetlearn newsletters.
    • More